From the collection of the
o Prejinger
v IJibrary
P
San Francisco, California
2007
VOL. XX NO. :
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
JANUARY, 1933
PUBLISHED MONTHLY BY THE
SOCIETY OF MOTION PICTURE ENGINEER
The Society of Motion Picture Engineers
Its Aims and Accomplishments
The Society was founded in 1916, its purpose as expressed in its
constitution being "advancement in the theory and practice of mo-
tion picture engineering and the allied arts and sciences, the standardi-
zation of the mechanisms and practices employed therein, and the
maintenance of a high professional standing among its members."
The Society is composed of the best technical experts in the various
research laboratories and other engineering branches of the industry
in the country, as well as executives in the manufacturing and produc-
ing ends of the business. The commercial interests also are repre-
sented by associate membership in the Society.
The Society holds two conventions a year, one in the spring and one
in the fall. The meetings are generally of four days' duration each,
and are held at various places. At these meetings papers are pre-
sented and discussed on all phases of the industry, theoretical, techni-
cal, and practical. Demonstrations of new equipment and methods
are often given. A wide range of subjects is covered, and many of the
authors are the highest authorities in their distinctive lines.
Papers presented at conventions, together with contributed arti-
cles, translations and reprints, abstracts and abridgments, and other
material of interest to the motion picture engineer are published in
the JOURNAL of the Society.
The publications of the Society constitute the most complete exist-
ing technical library for the motion picture industry.
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
Volume XX JANUARY, 1933 Number 1
CONTENTS
Page
The Problem of Motion Picture Projection from Continuously
Moving Film F. TUTTLE AND C. D. REID 3
Wide Screen Photography with Cylindrical Anamorphosing
Systems and Characteristics of Motion Picture Lenses and
Images H. S. NEWCOMER 31
Photographic Effects Obtained with Infra D Negative
D. R. WHITE 54
"narks on the Making of Sound Records on Lenticular Color
1ms A. P. RICHARD 60
ing a Fade-Out by After Treatment
C. E. IVES, L. E. MUEHLER, AND J. I. CRABTREE 65
ical Problems in the Recording and Reproduction of Music
for Motion Pictures D. MENDOZA 79
New Apparatus 84
Book Review 88
Officers 89
Society Announcements 90
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
SYLVAN HARRIS. EDITOR
Board of Editors
J. I. CRABTREE, Chairman
L. DE FOREST A. C. HARDY F. F. RENWICK
O. M. GLUNT E. LEHMANN P. E. SABINE
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.
Publication Office, 20th & Northampton Sts., Easton, Pa.
General and Editorial Office, 33 West 42nd St., New York, N. Y.
Copyrighted, 1933, by the Society of Motion Picture Engineers, Inc.
Subscription to non-members, $12.00 per annum; to members, $9.00 per annum,
included in their annual membership dues; single copies, $1.50. A discount
on subscriptions or single copies of 15 per cent is allowed to accredited agencies.
Order from the Society of Motion Picture Engineers, Inc., 20th and Northampton
Sts., Easton, Pa., or 33 W. 42nd St., New York, N. Y.
Papers appearing in this Journal may be reprinted, abstracted, or abridged
provided credit is given to the Journal of the Society of Motion Picture Engineers
and to the author, or authors, of the papers in question.
The Society is not responsible for statements made by authors.
Entered as second class matter January 15, 1930, at the Post Office at Easton,
Pa., under the Act of March 3, 1879.
THE PROBLEM OF MOTION PICTURE PROJECTION
FROM CONTINUOUSLY MOVING FILM*
FORDYCE TUTTLE AND CHAS. D. REID**
Summary. — The advantages claimed for non-intermittent projectors are presented,
followed by a list of questions that the writers think should be answered with regard
to any projector of this type. The various projector types are then classified ac-
cording to the optical means used to form a fixed image. Two types of error are
noted and each type of projector listed is discussed, keeping these in mind. A reference
table is appended to serve as a rapid review.
It has been the privilege of the authors to review the several
hundred patents which have been granted on non-intermittent mo-
tion picture projectors. We have found that the problem of producing
a satisfactory screen image from moving film by means of moving
optical parts is not a simple one, and it seems desirable to discuss the
difficulties encountered in the design of the several types of such
projectors.
Since any non-intermittent projector would have to compete with
the intermittent machine, and since the optics of the former ad-
mittedly will have to be more complicated, we must consider what
offsetting advantages may be possessed by the non-intermittent
projector.
A summary of the advantages claimed follows:
(1). There might be less wear and tear on film which is pulled at a
constant linear velocity through a machine than on film which is inter-
mittently accelerated by a machine.
(2) . There would probably be less difficulty in running film already
damaged through a non-intermittent machine. With the intermittent
projector, a few successive damaged perforations cause the loss of the
loop, and further damage to the perforations until the loop is restored.
The non-intermittent machine will usually restore itself to a running
condition even though the film be damaged over a considerable
length.
* Reprinted from /. Opt. Soc. of America, 22 (Feb., 1932), No. 2, p. 39.
** Eastman Kodak Co., Rochester, N. Y.
4 F. TUTTLE AND C. D. REID [J. S. M. P. E.
(3). There is a possibility that there might be more total light to
the screen, since no shutter is needed to cover up the movement of the
film.
(4). There might be a better portrayal of action if each picture is
allowed to blend into the successive picture.
(5). If the light to the screen can be kept constant at all times
during the projection cycle, it may be possible to eliminate flicker
entirely. Some inventors have argued that the interruptions of the
light, even though of frequencies high enough to eliminate visible
flicker, cause some eye-strain.
(6) . The ideal non-intermittent machine might be much less noisy.
In the present intermittent machine, certainly a large part of the
noise comes from the intermittent pull-down and from the film moving
intermittently in the loops and through the gate.
(7) . There might be less trouble with wear in the non-intermittent
machine. In the intermittent machine, wear in the pull-down parts
causes unsteadiness.
(8). In a portable sound-on-film projector, there might be a
number of mechanical advantages in not having to have the film
moving intermittently at the picture aperture and continuously at
the sound gate.
None of these possible advantages is great enough to offset any
serious imperfections in the projected picture, such as unsteadiness,
distortion, and poor definition. This does not mean that we would be
right in insisting on theoretical perfection in the projected picture.
Practically every non-intermittent machine involves approximations,
and in studying these machines we have found it desirable to set up
more or less arbitrary standards for theoretical steadiness, distortion,
and definition. If we make these standards about equivalent to the
practical standards of the intermittent machine, we could allow about
the following approximations:
(1). Steadiness of the center part of the picture plus or minus
0.0005 inch (referred to the film frame).
(2) . Distortion movement in the corners of the frame plus or minus
0.001 inch.
(3). Definition.
(a) . In the center of the frame 0.001 inch (circle of confusion) .
(b). In the corners 0.002 inch.
With intermittent equipment, considering the errors in the camera,
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION 5
the printer, and the projector, we are fortunate if successive frames
are registered in the projector gate closer than plus or minus 0.0005
inch, which makes our steadiness tolerance seem reasonable. Twice
the movement has been allowed in the corners of the frame that was
thought permissible for the center of the frame, because of the belief
that the eye is not particularly concerned with movement away from
the center of interest. The definition tolerances used here are
equivalent to those usually found in practice in motion picture work.
With regard to definition, it has been observed that if the definition
is poor during some parts of the projection period, but good during
other parts of the projection period, the eye sees definition that
is somewhat better than the arithmetical time average of the defi-
nition.
Before listing the different classes of non-intermittent projectors
and outlining the difficulties encountered in their design, the following
questions are presented as those which we think should be answered
with regard to any of these projectors.
QUALITY OF PROJECTED PICTURE
(1). Is the center point of the picture stationary within sensible
limits?
(2). Does distortion give a "rubbery" effect in the picture, or
does it make corner definition too poor to be acceptable?
(3). Is the definition in the picture comparable with intermittent
projection?
(4). Is the picture made flat by flare from many free glass-air
surfaces ?
(5) . Does the system permit of fading out of one picture into the
next?
AMOUNT OF LIGHT FOR PROJECTION
(6). Does the system impose limitations on the/ aperture of the
projection lenses?
(7). Is the light lost by passing through many surfaces or from
reflections serious?
(8). Is the light to the screen during the change-over period equal
to the light when projecting wholly from a single frame, or is it neces-
sary to introduce diaphragms or shutters which cut down on the
light?
(9). Does the system require a special moving condenser system?
6 F. TUTTLE AND C. D. REID [J. S. M. P. E.
PRECISION REQUIREMENTS
(10). If cams are used, what is the precision required in cutting
the cam? Are the surfaces such that they can be cut with precision
from point to point?
(11). What precision is required in the gear trains connecting film
drive with optical displacement means?
(12). What precision is required in the sprocket exactly fitting
the film? Is a jump back as one tooth leaves a perforation and the
next tooth starts to drive serious?
(13). What precision is required in initial adjustment?
(14). What precision is required in the making or matching of
optical parts?
SPECIAL LIMITATIONS
(15). Does the system impose impractical limitations on the
equivalent focus or the back focus of lenses?
(16). Does the system demand ridiculous physical dimensions
in the projector?
(17) . Does the system necessitate a fixed screen distance or a fixed
magnification?
(18). Is the system capable of projecting lenticulated color film?
(Kodacolor.)
(19). Is a special arrangement of pictures on the film or a special
type of film assumed?
(20) . What type of framing device is required ?
NOISE
(21). Are all moving parts moving with constant angular velocity
and can all of them be counterbalanced?
(22). How does the mass and moment of inertia of reciprocating
parts compare with the mass and moment of inertia of the inter-
mittent projector parts?
OPTICAL REQUIREMENTS DIFFICULT TO FULFILL
(23). Is it necessary to use simple lenses of large / apertures
covering large fields?
(24) . Is it assumed that a single image-forming reflector working
with a large aperture will cover a considerable field?
(25) . Is it necessary to assume that a warped reflecting or refract-
ing optical part can be made with great precision?
(26). Does the system demand the use of large aperture crossed
cylindrical lenses to work as a well corrected spherical lens?
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
i
It is conceivable that any device for refracting or reflecting light
might be used to give an optical displacement to an image which
ould compensate for the movement of the film. The following
ist indicates the elements which have been used, with a very short
description of how they were moved.
Moving Lenses
Reciprocating lens
Linear motion of lenses in restricted path
Circular motion (optical axes describing cylinder)
Circular motion (optical axes radial)
Circular motion of cylindrical lenses
Plane Parallel Plates
Uniformly rotating cube or hexagonal prism
Cam rotated plate
Uniformly rotating plate with normal to the plate describing a cone
Refracting Prisms
Cam actuated variable angle liquid prism
Uniformly rotating warped refracting elements
Equal prisms, cam rotated equally and oppositely
Reflecting Plane Mirrors
Cam reciprocated mirror
Cam actuated series of mirrors
Uniform rotating drum of mirrors
Helical reflecting surfaces
Rotating rhombs
Moving right angle reflectors
Skewed Image Forming Elements
Concave spiraled mirror
Spiraled lens
In the discussion of these displacement means, we would like to
point out two types of errors that occur:
(1) . Errors that are inherent in the displacement means employed.
(2). Errors that result from the method used in moving the dis-
placement means.
MOVING LENSES
Perfect lenses can be moved theoretically in such a manner that
there is no inherent defect in the displaced image produced. In prac-
tice the means of moving the lenses and the use of simple lenses intro-
duce difficulties.
If we move a lens, as in Fig. 1, in such a way that a straight line at
all times passes through the center of the picture frame, the center of
the lens and the center of the screen, we will have a stationary image
8
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
on the screen from film which is moving. We can design a cam which
will reciprocate a single lens in this manner, but we must have a
shutter which will cover up the return of the lens, and must introduce
flicker blades which will give high-frequency interruptions. Further,
the cam would have to be accurate to plus or minus 0.0005 inch.
The mass we are accelerating in such a system is larger than in an
LENS
GATE
SCREEN
FIG. 1. Optical compensation for film motion by a single moving lens.
intermittent projector, and the same aperture lens can not give the
same amount of light to the screen without a larger source or a moving
condenser system.
Our first attempt at improvement on this system probably would be
to try to have a series of lenses moving in a straight path in front of
the film so spaced that when one lens is following one frame from
LEN5
GATE
SCREEN
FIG. 2. Optical compensation for film motion by a plurality of moving lenses.
the top to the bottom of a two-frame aperture, the next lens is ready to
follow the next frame. This system would allow us to do without the
shutter for covering the return of the lens. It would be very difficult,
however, to keep the light to the screen constant as we change from
one frame to the next, and we would very likely end up with some type
of shutter or diaphragm in the system which would reduce the light.
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
With two lenses in the position shown in Fig. 2, we can see that the
physical diameter of the lenses is limited to a little less than the
height of the frame. If the lens has a focal length long enough to
cover the frame satisfactorily, we find that this limits the / aperture
VIRTUAL IMAGE
STATIONARY \ / MOVING LENS
LENS '
SCREEN
FIG. 3. Optical compensation for film motion by a plurality of moving lenses
and a fixed lens forming a virtual image of moving film.
to a maximum of something like //4, if we allow a minimum of lost
space for the mount.
We can gain considerably in the aperture of the system if we use
the arrangement shown in Fig. 3. A stationary lens subtending an
FIG. 4. One type of con-
stricted path to give a linear
motion to the moving lenses.
f/2 angle forms an enlarged virtual image of the film and the moving
lenses move so that a straight line connects the center of the virtual
image, the center of the moving lens, and the center of the screen.
With 16-mm. film projected with the equivalent of a 2 inch lens, we
10
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
can have//2 light to the screen at all times using moving lens elements
which have apertures of only about //6. With this system the ratio
of the physical diameter of the moving element to the diameter of the
stationary lens will determine the manner in which we may fade out
FIG. 5. Two wheels of lenses used to avoid the horizontal displacement
produced by a single wheel.
of one picture into the next. If the diameter of the moving element
is equal to the diameter of the stationary element, we will be con-
stantly changing from one picture to the next. If the diameter of
the moving element is much larger than the diameter of the stationary
lens, we may divide the projection cycle so that during only half the
time we are fading out from one picture to the next.
FILM OR VIRTUAL MOVIN6 LENSES
IMAGE OF FILM
SCREEN
FIG. 6. Optical diagram showing the paths of rays through the double wheel of
lenses.
With 35-mm. film projected with the equivalent of a 5-inch lens,
we can get//2 light again by using //6 elements. With either film,
if we can afford to increase the equivalent focus of the projection
system, we can use moving elements which have smaller / apertures
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION 11
and have to cover smaller angular fields. Thus, we see that it may
become possible for us to use comparatively simple moving lenses
which is much better than having to use and to move a lot of well
corrected lenses.
Other arrangements of a moving-lens optical system are possible.
The moving lenses working on real or virtual objects can be used to
form stationary real or virtual images. It is possible also to consider
negative lenses in some cases for the moving lenses. Detailed dis-
cussion of all types is beyond the scope of this paper.
The problem of moving lenses in a straight path at a constant linear
speed past the gate is not very easily solved mechanically. Several
inventors have shown lenses in a belt which move in a restricted
path as shown in Fig. 4, with the lenses either linked together or
crowding each other along in a channel with a drive for the lenses
supplied at some circular part of the path by some kind of rotating
sprocket. Such a system, however, is usually noisy and inconvenient.
Fig. 5 shows the lenses arranged about a wheel. A single wheel
would give the lenses an undesired horizontal displacement equal to
the sagitta of the arc over which the lens is used. The optical effect
of the horizontal displacement can be offset, however, if a similar
wheel of lenses rotating about another axis is used as shown in Fig. 5.
Fig. 6 is a top view of the lenses arranged in two wheels, showing how
the horizontal displacements of the two lenses are opposite; they
can be made to give zero optical displacement, if the focal length and
the magnification for each lens are correct. The vertical component of
the displacement varies as the sine of the angle through which the
lens wheel is rotated. If we turn the wheels at a constant angular
velocity, we will find it necessary then to have the film pass over a
curved gate, if we insist that the image of the center point of the
frame be made exactly stationary on the screen. The use of this
curved gate, however, will introduce distortion in the picture. By
making a compromise between distortion and steadiness, satisfactory
projection can be obtained with the system described if the two
wheels used each contain a sufficient number of lenses.
Fig. 7 shows another arrangement of lenses in a wheel. This
arrangement of lenses, when used with a straight gate, will give un-
desirable keystoning of the image on the screen, since all parts of the
film are not the same distance from the plane of the lens. Even a
curved gate will not rid us of this defect for the image plane is not
fixed. Fig. 8 shows the way the image surface shifts with respect
12
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
to the screen. However, if enough lenses are used in the wheel,
satisfactory projection can be achieved.
The problem of moving cylindrical lenses in such a manner that
the image will appear stationary is not as difficult as is the problem
FIG. 7. A drum of lenses used for optical compensation.
of moving spherical lenses, since we do not have to worry about any
horizontal displacement of the lens element in moving down across
the gate. The difficulty of using cylindrical lenses is an optical one.
It is necessary to assume that crossed cylindrical components, one
GATE:
MOVING LENSES
\
SCREEN
FIG. 8. The optical diagram for the system shown in Fig. 7.
moving, one stationary, can be designed to behave like a well corrected
spherical lens.
REFRACTING PRISM
The refracting prism stationary in the beam produces defects in the
image, giving errors of the first type. The problem of changing the
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
13
refracting angle of the prism in a satisfactory manner is difficult and
in some cases produces errors of the second class.
If the prism is used in the beam on the long optical side, as shown in
Fig. 9, or even in collimated light, we produce distortion in the image.
If the motion picture frame to be projected is entirely above the
LENS
MOVING PRISM
SCREEN
GATE:
FIG. 9. The distortion produced by a prism on the long optical
side of the projection lens.
optical axis of the lens and if we use a prism strong enough so that
the light from the center point of the picture passing through at
minimum deviation will be deviated so as to fall on the center of the
screen, light from the top of the frame will pass through the prism at
some angle differing from minimum deviation and will be bent more
SCREEN
FILM PRISM LE:NS
FIG. 10. The astigmatic effect caused by a prism on the short optical
side of the projection lens.
than it should be. Light from the bottom of the frame will also be
bent more than it should be. This will cause a lengthening of the
top part of the image and a shortening of the bottom part of the
image. If the prism is used on the short optical side of the lens, as
shown in Fig. 10, light from a point on the film going to various parts
14
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
of the lens will be deviated varying amounts, and the point will be
imaged on the screen as a line of considerable length.
Fig. 1 1 shows the departure in the angle of deviation from minimum
deviation for rays passing through prisms at various incident angles.
That these departures are serious is shown from a consideration of the
fact that a departure of one minute in angle with a 2-inch lens would
produce a displacement in the center part of the picture equivalent to
0.001 inch on the film frame, if the prism is assumed to be close to the
- DEPARTURE FROM —
MINIMUM DEVIATION
MINUTES
10° PRISM
f~
•#
I
-A' -2*
+2* +4° *6° +8" HO*
DEPARTURE FROM INCIDENTANG
FOR MINIMUM DEVIATION-
FIG. 11. The departure from minimum deviation produced by changing
incident angle.
lens or on the long optical side. If the frame subtends an angle of
10 degrees at the lens, a 10-degree prism is necessary to shift the
image one-half frame on the screen. If we consider the center part
of the picture at all times passing through the prism at minimum
deviation, rays from the top of the picture will be incident on the
prism, at angles differing from the incident angle for minimum devia-
tion by 5 degrees. This would be serious. However, it may be
perfectly feasible to use a refracting prism on the long optical side
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
15
if the film frame subtends a small angle at the lens, or on the short
optical side if the lens subtends a small angle at the film frame.
Fig. 12 shows a method by means of which we might partially
correct for deviation troubles. By using two prisms so tilted with
respect to each other that the ray which passes through the first
FIG.
12. A suggestion to eliminate the distortion caused by the
variation of deviation of a prism with incident angle.
prism at an angle differing greatest from minimum deviation goes
through the second prism at minimum deviation, and the ray passing
through the first prism at minimum deviation passes through the
second prism at an angle differing greatest from minimum deviation,
the total deviation produced in the two rays considered will be prac-
tically equal.
POSITION A
FIG. 13. A
method of con-
tinuously
changing the
angle of devia-
tion of a prism
to produce op-
tical compen-
sation.
POSITION B
FIG. 14. A second method of
continuously changing the angle
of deviation of a (compound)
prism.
As the film frame moves down over the gate, it is necessary to
change the refracting angle of the prism to keep the center point of
the image stationary. This changing of the angle of the prism is an
awkward problem. Two methods are fairly feasible. The first is
shown in Fig. 13 and consists of an annular disk which is ground so
16 F. TUTTLE AND C. D. REID [J. S. M. P. E.
that the refracting angle gradually changes from a prism with its
thick side toward the center of the disk to a plane parallel plate and
then to a prism with its thick side toward the circumference of the
disk. The use of this warped refracting element in a projector intro-
duces a skew distortion in the picture in addition to the distortions
already discussed for the fixed prism. These new distortions become
small if the prism disk is very large. The use of two warped refracting
elements may allow cancellation of the skew distortion. Such an
element is very difficult to make. Of course, it would be very difficult
to achromatize it. It might be argued that it is not necessary to
achromatize prismatic elements which appear in rapid succession
first base side up and then base side down in the beam because per-
sistence of vision would make superimposed complementary colored
fringes appear nearly colorless. The trouble with this argument,
however, is that the limit of definition of a horizontal line becomes the
width of the spectral image of that line.
Another method of changing the refracting angle of prism elements
is shown in Fig. 14. Two equal prisms placed with their emergent
and entrance faces together may form a compound prism that will act
as a plane parallel plate if the thick side of one is placed opposite the
thin side of the other, as shown in position A . Now, if these prisms
are each rotated through 90 degrees in opposite directions, we may
arrive to the position B, which gives us a compound prism of twice
the power of its component prisms. It will be noted that any hori-
zontal displacement produced by one prism is offset by an equal but
oppositely directed horizontal displacement produced by its com-
panion prism. The vertical refracting angle, however, varies sinu-
soidally from zero to twice the refracting angle of the single prism.
When prisms of this type are used in a non-intermittent projector,
it is necessary to reciprocate them angularly with some cam motion
and to have a shutter to cover the return.
PLANE PARALLEL PLATE
The mere presence of a tilting plane parallel plate used in the beam
of light produces defects in the image, while the method of tilting it
also presents some difficulties.
The plane parallel plate used in a non-intermittent projector will
have to be used on the short optical side of the projector system, or
else be tremendously thick, since the displacement produced by the
plate is a parallel one rather than an angular one. On the film side
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
17
of the lens a parallel displacement of a fraction of an inch will com-
pensate for the full movement of the film and shift the screen image
several feet.
Fig. 15 shows the displacement produced by a plane parallel plate,
and Fig. 16 shows the variation of this displacement with the angle of
tilt of the plate for a one-inch and a half -inch plate. It will be ob-
GATE
LENS
SCREEN
FIG. 15. The type of displacement produced by a plane parallel plate.
served that the relation is not a linear one, and hence the proper
movement of the plates constitutes a problem unless the motion is to
be controlled by a cam surface. The use of a plane parallel plate
normal to the axis introduces spherical aberration and astigmatism.
Fig. 17 shows how a point on the axis of the lens is imaged as a circle
of considerable diameter on the screen. Fig. 18 shows the direction
FIG. 16. The relation between the displacement produced by a plane
parallel plate and the angle of tilt of the plate.
of rays from a point off the axis of the lens if the rays pass through a
tilted plane parallel plate on the short optical side of the lens. The
apparent definition on the film is affected, then, by the use of the
plate and the position of the plate. If a 2-inch f/2 lens is used with a
plate one-half inch thick, all of the rays which reach the screen from
points on the film can be accounted for only if we imagine the points
18
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
on the film extended to a considerable size. The plane parallel plate,
in other words, is producing virtual images of the points and makes
them appear to the lens as disks or streaks. Fig. 19 shows the major
axis of the confusion disks for different points on the film and for
different angular positions of a one-half inch plate. It will be noted
that when the plate is tilted, the position of best apparent definition on
the film shifts. It is, of course, impossible to correct the lens by any
SCREEN
GLA55 PLATE LENS
FIG. 17. The circle of confusion on the screen produced
by the spherical aberration of a plane parallel plate on the
short optical side of the projection lens.
stationary means for this varying astigmatic effect. The use of a
similar moving plate on the image side of a one-to-one system might
seem at first to offer a chance for correcting the defect, but unfor-
tunately both spherical aberration and astigmatism in such a system
are additive. Probably the best the optical designer can do is to
correct the system for spherical aberration when the plate is normal.
FIG. 18. Blurred image on the screen produced by
a tilted plane parallel plate on the short optical side of
the projection lens.
It may be advantageous to use a long focal length lens when a tilting
plate is used. With a long focal length lens the definition is more
uniform over the area considered because the film frame subtends a
much smaller angle at the lens. It is not always advantageous to do
this, however. The dotted curve shown in Fig. 19 shows the major
axis of confusion disks for a 10-inch f/2 lens when a one-half inch
plate is tilted at 10 degrees. Comparison of the definition obtained
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
19
in this manner with that obtained with a one-half inch plate tilted at
10 degrees with the 2-inch f/2 lens shows that we do not gain in defini-
tion until we get some distance below the axis or considerably above
the axis.
The size of the astigmatic image is very materially reduced if the
aperture of the lens is limited in the vertical dimension. We have to
consider only a small pencil of rays passing through the plate. There
-J
2 .3 A 5 .6
DISTANCE OF POINT FROM
.8
FIG. 19. The magnitude of the major axis of confusion disk caused by a one-
half inch plane parallel glass plate in conjunction with a 2 inch//2 projection
lens as a function of the distance of the object point off the axis for different
tilts of the plate. The dotted curve refers to a 10 inch//2 lens with the plate
tilted at 10 degrees.
are two unfortunate things about limiting this vertical angle, however:
one, considerable light is lost and, two, it does not rid us of the distor-
tion effect which is present with a tilted plate. Fig. 20 shows dia-
grammatically how this distortion is produced.
Under certain conditions the distortion effect may be improved
by using two plates, each of half the original single -plate thickness,
placed one on each side of a one-to-one optical system, as in Fig. 21.
20
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
When the plates are normal to the optic axis there is no distortion.
When the plates are tilted, the distortion is somewhat corrected.
If we are willing to use a cam to oscillate the plate and a long focal
length lens with a restricted vertical aperture, we can have theoreti-
cally good projection with a single plate tilting in the beam. The
LENS
SCREEN
FIG. 20. Distortion produced by a plane parallel plate
on the short optical side of the projection lens.
screen picture, however, would be small unless we relay the image.
The loss of light in such a system, especially with the relay and with a
shutter which would cover the return of the plate and have flicker
blades, would rule out such a projector.
FILM
GLASS
PLATE
SCREEN
FIG. 21. The partial correction of the distortion
produced by a plane parallel plate by the use of two
similar plates on opposite sides of a lens working at
unit magnification.
If we want to follow the film with uniformly rotating plates, we find
in Fig. 22 that we will have to use a plate 3 inches thick, even for
following 16-mm. film over the displacement of plus or minus half a
frame, if we are to stay within our steadiness tolerance of 0.0005
inch. We can rotate this plate through an angle of only 8 degrees and
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
21
since we will have to have another plate ready to follow the next
frame, we will have to have 48 plates arranged on a drum. Such a
projector would be quite impracticable.
A very ingenious use of parallel plates can be found in one pro-
jector. By arranging plates as shown in Fig. 23 with the plates
making an angle with their axis of rotation, but normal to the optical
axis in their mid-position, it is possible to have the vertical com-
Q
9 10
t IN INCHES
FIG. 22. The departure from a linear relation between the displacement
produced by a plane parallel plate and the angle of tilt with respect to plate
thickness, for various total displacements.
ponent of the displacement produced very nearly linear with the
angle of rotation. The undesired horizontal component of the dis-
placement can be compensated for by having other plates rotating
in the same manner some place in the system in such a way that the
vertical displacements are additive and the horizontal displacements
offset one another. With this arrangement it is still necessary, how-
ever, to restrict the vertical angles subtended by the lens to get rid
of astigmatism.
22
F. TUTTLE AND C. D. REID
MOVING MIRRORS
[J. S. M. P. E.
Plane reflecting surfaces can be used in the beam without producing
any defects in the image. The single tilting mirror, however, can not
be used alone without distorting the image. The method used for
moving reflecting elements also introduces errors in the image.
In Fig. 24 there is shown a reflecting mirror tilted in the long
AXIS OF
ROTATION
OPTICAL AXIS
AXIS OF
ROTATION
OPTICAL AXIS
FIG. 23. A special method of tilting plane parallel
plates to produce a good approximation to a linear rela-
tion between the vertical component of the displacement
and the angular displacement about the axis of rotation of
the plates.
optical side of a projection system. When the mirror is at 45 degrees
the plane of the image formed by the system makes an angle of 90
degrees with the plane of the film gate. If the mirror is tilted through
an angle sufficient to place the center of the frame, which is entirely
above the axis of the lens on the center of the screen, the plane of the
image does not correspond with the plane of the screen but falls along
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
23
the dotted line shown in Fig. 24. The image is rectilinear in its
plane but, of course, is not projected on to the screen plane as a
rectilinear image, nor is it exactly in focus. Because the image plane
does not correspond to the screen plane, the screen image is dis-
torted in two directions. Vertical lines on the film will not be parallel,
the top edge of the picture being either narrower or wider than the
bottom edge of the picture/ Horizontal lines on the picture will be
imaged as parallel lines on the screen, but horizontal lines equally
spaced on the film will not be equally spaced on the screen. If the
angle through which the mirror has to be tilted to keep the center of
PLANE: or rocus
WITH MIRROR TILTED
5CREEN
MOVING M/RROR
GATE
FIG. 24. Optical compensation for the film motion
produced by a tilting mirror in the light path.
the frame imaged on the center of the screen is small, this keystoning
distortion will not be serious. Hence, with a long focal length lens
we will be able to tilt the mirror by some cam mechanism and have a
satisfactory picture on the screen. If we want to avoid the use of
cams and change the angle of tilt of the mirror linearly with time,
we can mount a series of mirrors on the periphery of a drum and rotate
the drum with uniform angular velocity. This sort of system of
moving the mirrors, however, will affect the steadiness of the center
point of the picture on the screen. If we use a straight gate and the
film is moving at a constant linear speed through this gate, it is the
24
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
tangent of the angle which the center of the frame subtends at the
lens from the axis of the lens, which is going to vary linearly with
time and not the angle itself. Mr. H. Dennis Taylor in a paper
published in The Photographic Journal, February, 1924, has shown
that to get satisfactory projection with a system using a uniformly
rotating drum of mirrors with 35-mm. film, it is necessary to use about
60 mirrors in the drum. The possible ways that have been proposed
for reducing the defects produced in the image by a tilting mirror
have involved the use of curved gates and toroidal lenses. We feel
PRISM
FIG. 25. A method of following moving film by
the motion of a prism reflector.
certain that a curved gate could be used to correct to some extent for
the distortion in the image. A very satisfactory projector has been
designed which uses a series of cam actuated mirrors and a curved
gate. A discussion of nonrectilinear lenses is beyond the scope of this
paper.
Fig. 25 shows how two reflecting surfaces can be moved together
and keep the image from moving film stationary on the screen. In
this figure the reflecting surfaces are two faces of a right angle prism.
It is evident that the mechanical problem of moving a series of prisms
of this form at a constant linear speed and in a straight path in front of
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
25
the gate is difficult. The correcting element occupies considerable
space, and it is difficult to have a second element ready to follow a
second frame past the gate as soon as the first frame reaches the
bottom of the gate. Further, the size of the prism is considerable
and the back focus of the projection lens has to be long.
In Fig. 26 we have shown how reflecting surfaces of rhomb prisms
may be moved to give a vertical optical displacement of the image.
A single rhomb gives a parallel displacement to light which is equal to
the face of the rhomb. If the rhomb is held in one position in the
projection system, this displacement is all a vertical displacement.
FIG. 26. The use of pairs of reflecting rhombs to
produce a stationary image from moving film.
If the rhomb is rotated through 90 degrees, the vertical displacement
is zero, the. whole displacement being horizontal. Horizontal dis-
placements of course are not desired in a non-intermittent projector.
The figure shows how two rhombs may be rotated together in such a
manner that the horizontal displacement of the image is zero and
still allow a vertical displacement. If the wheels carrying the rhombs
are rotated with uniform angular velocity, the displacement effected
by the system varies not linearly but sinusoidally with time. Here
again, then, we see that we will have to use a large number of rhombs
to get satisfactory projection. We would like to point out that the
26
F. TUTTLE AND C. D. REID
[J. S. M. P. E.
.= iss
sail
lia~
ti
JM
! s
L. ¥ 3
s-aS
(
«1
El!
£32
&) <D
.S d £
S ° S
o3 "S „; fa
jj rt ™ O
£ ^ S 2
Q O 3 S
1 1
II
(6
T— t
I
^ '
*l
II
Precision
Requirements
o <u
•^
. .
,D fl «+_ <L) rt
i J 5 If 1
i
^5 -i a a -i
I.23
-M O
•S?
11
*3
a|
bo p
fi'Q*
C -g bo
<U '3 '43
a ^
S-ss
a 8 to a
la
S a o
.-I 3 S
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION
27
l1-
Ijfl
CM OJ
O .d
•4-1
The longer
length
better
•83?
S^-°
-M flj JH ^
tj
! «
££
"So 3
f * ! Pi
es3l sfl
CQ <H
i!L
A
ty
ha
Le
m
wjS
en en
'•S •5
H ^
Long
required.
I
g S
oj T3 43
•Sil
X
•5?
'•
& «r* 2 "—i bo
•s ^ rt *i -a -d
'§ o 3 § -a g
p, -M o g
IH r« _ b> *i SH
^
iJ S
S S
£ <<
<< .= .a S S I
3 6 o
2 -S. |
fi
'i-5
s
•jS ^3 OT
°
o
1
1-1
5 S. §
28 F. TUTTLE AND C. D. REID [J. S. M. P. E.
path between the film and the lens is very long and we will have to
use a long back focus lens for projecting with this system.
SKEWED IMAGE-FORMING REFRACTING OR REFLECTING ELEMENTS
A number of inventors have proposed the use of spiral image-form-
ing refracting or reflecting elements. These elements, of course,
would be very difficult to make. Their only advantage would likely
be in the fact that they would simplify the problems of moving the
optical part in the beam. Their use would probably introduce a
twisting distortion in the image.
SUMMARY
We know that the four types of elements — lenses, prisms, plates,
and mirrors — can be used under proper conditions to produce satis-
factory pictures as far as quality is concerned. The projected picture
is steady enough, free enough from distortion, and the definition is
passable. It is possible to have the number of glass-air surfaces small
enough so that the picture is not made flat because of flare. In some
cases we have found that the focal length of the lens has to be longer
than desirable, and we might have to use a relay system for getting
the image large enough on the screen. These relay systems would
introduce additional surfaces which certainly may lose a considerable
amount of light. In some cases we found that to get a satisfactory
picture we had to limit the / aperture of the projection lens. This,
of course, will cut down on light. We have not discussed very fully
the problem of keeping the light constant to the screen during the
period which we use to change over from projecting from one frame
to projecting from the successive frame. Any method we use, how-
ever, is very likely to limit the light to some part of the picture during
the change-over period. With moving lenses there will be some
barrel cutting and some loss of light from points which are consider-
ably off the axis of the lens. With prisms we can not change suddenly
from a prism base side up to a prism base side down without cover-
ing up the period of that change. Plane parallel plates joined to-
gether so as to pass successively in front of the gate will have a divid-
ing line between plates, which appears to the film, because of refrac-
tion, to have considerable width. Even mirrors can hardly be
joined together so that the dividing line between them is fine enough
not to affect the light to the screen. Any change in the amount of
light to the screen during the projection period demands the use of a
shutter and flicker^blades or some fixed diaphragm which will keep
Jan., 1933] CONTINUOUSLY MOVING FlLM PROJECTION 29
the light constant. Either method will lose light to the screen.
Many of the systems require a moving condenser system to get even
illumination.
The precision requirements on the mechanical parts used in a non-
intermittent projector can be computed by finding the angle or dis-
tance through which we can move the optical elements with the film
stationary without shifting the image on the screen in an objectionable
amount. The pitch of the sprocket must be equal to the pitch of the
film to within 0.0005 inch in one perforation pitch if we are going to
project the picture continuously and keep that picture steady on the
screen. It may be necessary to have the optical elements used
precisely matched, and the initial adjustment of the elements pre-
cisely made. These precision requirements, of course, will add to the
cost of producing the projector.
If we are going to gain in quietness of the projector, we can not
rapidly reciprocate parts which have considerable mass or moments of
inertia. We can gain in quietness, however, if the projector design
allows us to move all parts with constant angular velocity and have
all parts counterbalanced. Many of the systems proposed impose
special limitations on the projector. For some of them to work satis-
factorily they would have to have ridiculous physical dimensions.
vSome of them demand a fixed screen distance or a variable focal
length auxiliary projection lens. Some of them demand a special
arrangement of pictures on the film. Several do not provide any
framing for the picture except at the screen. Very few of them
could be considered as projectors for projecting lenticulated color
film.
BIBLIOGRAPHY
JENKINS, C. F.: "Continuous Motion Picture Machines," Trans. Soc. Mot.
Pict. Eng. (May, 1920), No. 10, p. 97.
JENKINS, C. F.: "Continuous Motion Projector for the Taking of Pictures
at High Speed," Trans. Soc. Mot. Pict. Eng. (May, 1921), No. 12, p. 126
JENKINS, C. F.: "Prismatic Rings," Trans. Soc. Mot. Pict. Eng. (May, 1922),
No. 14, p. 65.
STEWART, FRANK N.: "Note on New Continuous Projector," Trans. Soc.
Mot. Pict. Eng. (May, 1922), No. 14, p. 162.
FORCH, C.: "Der optische Ausgleich der Bildwanderung in der Kinemato-
graphie," Zeit. Wiss. Phot. (1921-22), No. 21, p. 201.
BENNET, C. N.: "Continuous Motion Projectors," Kinemat. Weekly (Jan.
11, 1923), No. 71, iv.
TAYLOR, H. D.: "The Feasibility of Cinema Projection from a Continuously
Moving Film," Trans. Opt. Soc. (1923-24), No. 25, p. 149.
30 F. TUTTLE AND C. D. REID
WEISS, K.: "Die Ringlinse als optischer Ausgleich der Filmbildwanderung,"
Phot. Ind. (Aug. 22, 1923), p. 419.
BOWEN, LESTER, AND GRIFFIN, HERBERT: "Is the Continuous Projector
Commercially Practical?" Trans. Soc. Mot. Pict. Eng. (May, 1924), No. 18, p. 147.
RUHNAU, R.: "Projektoren mit optischem Ausgleich," Kinotechnik (Oct. 20,
1927), No. 9, p. 529.
LEVENTHAL, J. F.: "Projectors with Optical Intermittents," Trans. Soc.
Mot. Pict. Eng., XII (Apr., 1928), No. 34, p. 406.
LEVENTHAL, J. F.: "A New Optical Compensator," Trans. Soc. Mot. Pict.
Eng., XII (Sept., 1928), No. 36, p. 1068.
HOLMAN, A. J.: "A Non-Intermittent Optical Projector," Trans. Soc. Mot.
Pict. Eng., XII (Sept., 1928), No. 36, p. 1184.
"The Mechau Projector," Trans. Soc. Mot. Pict. Eng., XII (Sept.. 1928), No.
36, p. 1193.
HATSCHEK, P.: "Optical Compensation in Photography and Projection,"
Kinotechnik (July, 1929), No. 11, p. 367.
HOLMAN, A. J.: "Apparatus Developed to Simplify Manufacture of Lens
Wheels for Continuous Projectors," /. Soc. Mot. Pict. Eng., XIV (June, 1930),
No. 6, p. 623.
CoNTiNSOUZA-CoMBEs: "Note sur la Projection a Deroulement Continu et
1'appareil Continsouza-Combes," Butt. Soc. Franc. Phot. (May, 1928), No. 15,
p. 119.
WIDE SCREEN PHOTOGRAPHY WITH CYLINDRICAL
ANAMORPHOSING SYSTEMS
AND
CHARACTERISTICS OF MOTION PICTURE LENSES
AND IMAGES*
H. SIDNEY NEWCOMER**
Summary. — This paper presents a brief description of the advantages of optical
compression for producing wide screen pictures. There is included an exposition
of the design and operating characteristics of cylindrical compression objectives,
with particular reference to the high degree of central and marginal definition at-
tainable. This latter is compared with the performance of existing motion picture
lenses. In this connection there is presented a detailed quantitative description of
the definition attainable with high-grade motion picture lenses. These data are
correlated with information as to the physiological requirements for satisfactory
definition on the screen.
INTRODUCTION
All lenses of whatever nature fall short of producing perfectly
sharp images. Satisfactory motion pictures are possible because
in the conditions under which the pictures are observed the eye does
not readily detect imperfections that are below a certain level.
The choice of any method of producing wide screen pictures will
depend to a considerable extent on the possibility of obtaining
images of suitable quality. If a method that produces suitable
images be also economical and easy to apply, the combination is
ideal. If the method be neither economical nor optically satis-
factory, it has little to recommend it.
In order to form an intelligent opinion about the relative merits of
different methods of producing wide screen pictures, one must have
certain precise information about the definition that is obtained with
motion picture lenses on standard film and how this definition is
influenced; in the one case by optical compression with cylindrical
lenses, and in the other case by increasing the width of the film and
* Presented at the meeting of a New York Section, June 8, 1932.
* * Consulting engineer, New York, N. Y.
31
32 H. S. NEWCOMER [j. s. M. P. E.
the area to be sharply covered by the lens. It is from this point of
view that the subject is here presented.
This paper presents a brief description of the design and operating
characteristics of cylindrical compression objectives together with an
account of their advantages and performance possibilities when used
to produce wide screen pictures on standard motion picture film.
The subject is presented both from the point of view of the perform-
ance of existing lenses and of the mathematical and physiological
considerations fixing the optimum quality of projected images. It is
shown that all the better motion picture lenses approach a quality
that is little more than sufficient to meet modern theater require-
ments.
The central portions of the picture are naturally subjected to the
closest scrutiny, and there the best definition attainable is almost
twice what the critical observer requires. On the other hand, the
peripheral portions of the image are much worse, being subjected to a
number of deteriorating influences that appreciably increase as the
border of the present image frame is reached and passed.
OPTICAL ADVANTAGES OF STANDARD FILM
Thus, from an optical point of view, standard film has many ad-
vantages, and the importance of the dimensions of the frame in
forming suitably sharp images becomes apparent only after one
has had an opportunity to study the performance characteristics
of motion picture lenses. This not only has an important bearing
on the dimensional relations obtaining in present-day practice,
but it very seriously handicaps the use of wide film and affords a
considerable advantage to optical compression as a means of obtain-
ing laterally extended screen images.
Thus, from the point of view of sharpness of image, the results
attained by the compression or anamorphosing objective are superior
to those afforded by wide film. This advantage is by no means the
sole merit of the method. The anamorphoser comes into play only
twice in the entire sequence of operations from the taking of the
picture to its projection on the screen; namely, at the beginning,
when it is placed in front of the ordinary camera equipment used to
take the picture, and at the end, when it is placed in front of the
projector to expand the picture on the screen. In all the many
stages of processing and handling, the film is treated as ordinary
standard film, and the tremendous expense involved in providing
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 33
special equipment for processing, packaging, and projecting wide
film is all avoided. The anamorphoser permits wide screen pictures
of excellent quality to be shown interchangeably with standard pic-
tures, and the method may be used for either whole features or par-
ticular scenes as desired. Contrary to current opinion it is extremely
easy to mount cylindrical compression systems on both cameras and
projectors.
THE CYLINDRICAL COMPRESSION OBJECTIVE
In taking the picture, the effect of the anamorphoser is to com-
press a wide picture into a relatively narrow space. The compres-
sion is produced by a device that acts like an inverted telescope,
but in one meridian only. The cylindrical anamorphoser is com-
posed, in its simplest form, of a positive and a negative cylindrical
member with axes parallel and arranged in the manner of an ordinary
opera glass or Galilean telescope. The anamorphoser is afocal;
hence its interposition in front of the ordinary camera or projection
lens does not alter the focus of the lens. During the photographing,
the anamorphoser merely compresses the image of the laterally ex-
tended scene into a narrow film space; during projection it expands
the projected film image to an increased width on the screen.
The cylindrical anamorphoser is not a recent development, even
in motion picture work. Ernest Abbe many years ago described all
the types used today. At the beginning of the present motion pic-
ture era, Zollinger proposed to use them to compress the image and
save expenditure for film. It was only recently, however, that
serious attempts were made to rid these anamorphosers of the con-
siderable color and other imagery defects which they exhibited and to
correct them to the degree required in motion picture work. Many
attempts at improving the photographic quality of these systems
have not been very successful. Only a short time ago Mr. H. W. Lee,
in speaking before the Royal Photographic Society, called attention
to the fact that "the designing of these systems was exceedingly
laborious, and the manufacture of deforming systems with cylindrical
lenses far more difficult than of optical systems with spherical sur-
faces."
However, as is often the case, once a satisfactory solution has
been obtained, the problem appears much simpler. As a matter of
fact, if certain features of design be adhered to, features that involve
among other things the relative indices of the glasses used and the
orientation of the cemented surfaces and the cambrures of the ele-
34
H. S. NEWCOMER
[J. S. M. P. E.
ments, an extremely simple system that is unusually free from aberra-
tions of every sort can be designed. Figs. 1 and 2 show, respectively,
a photograph and a cross-section of a fully corrected anamorphoser,
and serve to illustrate its simple and compact construction. This
anamorphoser is used without any supplementary correcting system,
none being necessary.
FIG. 1. Cylindrical anamorphoser: left, mounted in front of a 1-inch
lens in company with a 2-inch and 4-inch lens on the same turret; right,
on a bracket suspending it in front of any of three lenses on turret.
The aberrations of cylindrical systems of this sort are, in a way,
analogous to those of spherical systems. In correcting for the
imagery at the central portion of the field, once axial astigmatism is
obviated by proper spacing arrangements, it remains only to rid the
system of spherical and chromatic aberrations. This may be done
by correcting each individual member separately. The residual
FIG. 2. A cross-section of a fully corrected anamorphoser.
secondary spectrum, and the zonal errors are then of similar magni-
tude and opposite sign, so that the assembled system may be ex-
ceptionally well corrected for axial image points. In fact, the writer
has found that by thus largely ridding each member separately of
spherical aberration, the zonal spherical aberrations of the system
as a whole may indeed be made so small as to have a maximum value
Jan., 1933]
WIDE SCREEN PHOTOGRAPHY
35
of one part in thirty thousand, equivalent to a longitudinal focusing
error of one part in one hundred and eighty thousand for an as-
sociated 50-mm. camera lens. The paraxial color focal difference in
the spectral interval C to F may be one part in seven thousand and
the zonal color differences one part in ten thousand, corresponding,
respectively, to one part in forty thousand and one part in sixty
thousand for the associated 50-mm. lens. These are, of course,
fantastically and unnecessarily small errors.
THE COLOR CORRECTION OF THE CYLINDRICAL OBJECTIVE
This leads us to a consideration of the color correction for marginal
or extra-axial points of the image. The writer has found it possible
by suitably constructing the two members, to eliminate astigmatism
and coma along inclined rays; in other words, to make all the rays
of any entering bundle of parallel rays traverse the objective and
emerge from it still parallel. (See Fig. 2, and Fig. 3 at C.) This
I0!60
Ot59
0!58
1057
FIG. 3. Curves showing, for a certain anamorphoser,
the angular spread of the three rays shown at the right in
Fig. 2 when the rays at the left are parallel and at an
angle of 7.05 degrees to the axis. Ordinates are angles
with the axis.
parallelism can be made practically absolute for all the rays of a par-
ticular bundle, provided the light is monochromatic. But if the
objective be composed, as just described, of members individually
fully achromatized in the usual manner so as to be, as far as possible,
free of color focal differences along the axis, there remains an ap-
preciable lack of parallelism of the different colored rays of an in-
36
H. S. NEWCOMER
[J. S. M. P. E.
clined bundle, and hence a color fringe in the marginal areas of the
picture. Fig. 3 illustrates the extent of such an error for a beam of
parallel rays inclined 7 degrees on the camera side. The abscissas
of Fig. 3 are wavelengths, designated by the conventional letters,
and the ordinates are the angles of emergence with respect to the
axis. Only the emergence angles for the central and two outside
C d e r q h
FIG. 4. Same as Fig. 3, but referring to an ana-
morphoser specially corrected to improve or narrow the
color dispersion in the region e to h.
rays of such a beam are plotted. (See also Fig. 2.) The maximum
entrance height on the positive member as plotted is 1/20 the focal
length of the member. This corresponds to a 15-mm. half -opening
on the objective used in the demonstration, half its maximum open-
6?I5
FIG. 5. Same as Fig. 3, but referring to an anamor-
phoser specially corrected to improve or narrow the color
dispersion in the region C to g, where visibility and Mazda
lighting are most effective.
ing. Fig. 2 shows the position of such a ray with respect to an as-
sociated/72.3 50-mm. camera lens.
The curves of Fig. 3 show an angular emergence difference for the
spectral interval C to h of 0.06 degree, corresponding to a diffusion
circle of 0.035 millimeter for an associated 50-mm. camera lens, the
angle being two- thirds as large on that side. At an inclination of
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 37
10.5 degrees, that is, for a point near the margin of the picture, the
difference is greater, and the diffusion circle is about 0.06 millimeter
in diameter. Although the actual effective error is somewhat less
than this, nevertheless it is added to the relatively poor marginal
performance of the camera and projection lenses, and therefore must
be reduced.
There is an unusual and interesting method of eliminating this
large marginal color error, namely, by only partially achromatizing
each of the two members of the anamorphoser. Fig. 4 gives the
curves for a 10. 5 -degree angle for an anamorphoser thus corrected,
in this instance in such fashion as to reduce the angular difference,
F to h, to about 0.01 degree at a fractionally smaller opening. The
operating characteristics of this anamorphoser are obviously excellent
when used for photography in daylight with either ordinary or pan-
chromatic stock. The marginal diffusion circle of the 50-mm.
camera lens caused by the anamorphoser is only 0.006 millimeter.
Fig. 5 represents a slightly lesser degree of primary underachromati-
zation, the purpose of which is to bring the maximum marginal
correction into the spectral region C to g. This anamorphoser gives
optimum results, either for projection or for studio photography.
In projection, although the absolute aperture is larger, the angle is
less, so that the curves are not much different.
For convenience in interpreting the significance of the color
corrections, there is drawn on Fig. 3 a sensitivity curve of Eastman
panchromatic emulsion. The curve is drawn to an arithmetical
scale, and not a logarithmic scale as is usually the case. The ordi-
nates are estimated from readings of wedge spectra, the curve being
then corrected by integrating various color regions and adjusting
the curve so that the integrals correspond to the respective published
exposure times.
In Fig. 5 are plotted a visibility curve and a sensitivity curve for
Mazda illumination. The sensitivity curve is derived from the
curve of Fig. 3 by multiplying the ordinates of Fig. 3 by the corre-
sponding ordinates of a tungsten filament emission curve and dividing
by those for daylight energy distribution. The abscissas of Figs.
3, 4, and 5, representing wavelengths, are drawn to logarithmic scale.
ERRORS OF CYLINDRICAL OBJECTIVE COMPARED WITH THOSE OF
CAMERA LENSES
Despite the existence of only a partial achromatization along the
axis of each of the two members, the objective as a whole yet has a
38 H. S. NEWCOMER [J. S. M. P. E.
very satisfactory paraxial and spherical color correction, one part in
seven hundred and one in a thousand, respectively. The resulting
diffusion circles for an associated 50-mm. camera lens are less than
0.002 millimeter in diameter, a value that, as will be seen, is too
small to produce any deteriorating effect on the quality of a motion
picture image. These figures (increased by 50 per cent for good
measure) for the diffusion circles at the center and margin of standard
film due to the anamorphoser are plotted in Fig. 7, where they may
be compared with the much greater diffusion of the image resulting
from the defects of the camera lens itself.
Since the anamorphoser is afocal, its relative opening depends only
on its absolute size. It is, in fact, convenient to choose the size so as
to reduce the aberrations considerably below those of the spherical
objective with which the anamorphoser is associated. The anamor-
phoser has, therefore, an almost negligible deteriorating effect upon
the image. In fact, the very slight effect observed must be attributed
almost entirely to the interposition of the four air-to-glass refracting
surfaces. It amounts at the most to a difference of one stop; and
since motion picture lenses are now available that are appreciably
more than this amount superior to most motion picture lenses now
in common use, it will be obvious that one can obtain all the ad-
vantages of the anamorphoser for the production of wide screen
pictures and yet retain the quality of picture to which the critical
observer is now accustomed.
Except for the slight effect of surface loss, the anamorphoser does
not increase the required exposure time. On projection, there is a
light loss due to the expansion, and which is proportional to the
expansion. We have experimented until we can print anamorphosed
film so that the projected image appears as brilliant as ordinary
screen images. Before this result was accomplished, it was found
possible and practicable to increase the arc current until anamor-
phosed and ordinary illumination of the screen, projected consecu-
tively from different machines, appeared equally brilliant. The
Scott Parrish single blade superspeed shutter passing about 50 per
cent more light without flicker by decreasing the occulting time, and
readily adaptable as it is to existing projectors, should put an end to
any necessity of increasing light.
The cylindrical anamorphoser consists of a positive and a negative
member so spaced as to give an afocal combination. The axes of
the cylinders are parallel; in fact strict parallelism is essential.
Jan., 1933] WIDE SCREEN PHOTOGRAPHY 39
The allowable errors in alignment are almost infinitesimal, but
mechanical and optical means for rapidly attaining and maintaining
suitable alignment have been devised, and have solved what at first
seemed to be an insuperable obstacle to the development of a good
objective. Similarly, means have been found of grinding and polish-
ing cylindrical surfaces so that they can be made as easily as spherical
surfaces and, as with the latter, to any degree of perfection that seems
necessary and desirable . Their manufacture is not in any sense a hand
process. The quality improves when the lenses are made in series.
FACTORS DETERMINING THE QUALITY OF THE ORDINARY MOTION
PICTURE IMAGE
Present-day motion picture photography and projection make de-
mands on the optical equipment that can be properly understood
only when three independent stages of the image-reproducing process
are analysed and subjected to quantitative measurement and inter-
pretation. Thus we have first to consider the quality of the image
on the negative film, an image that is carried essentially unchanged
to the positive film. Then the image must be projected by means
of an optical system that has, as we shall see, certain inherent limita-
tions. Lastly, the eye perceives the screen image and requires, for a
subjective sensation of sharpness and brilliance, that the blurring of
the details of the image shall not exceed amounts that we shall later
discuss and correlate with the definition obtainable. As the first step
we shall consider the photographic image.
THE NEGATIVE MOTION PICTURE IMAGE
Practical studio lighting conditions and emulsion speeds require
the use of relatively large aperture lenses, between f/2 and //3.
This means that the apex of the cone of light forming a point image
on the film embraces a rather large angle, and when not focused on the
film casts thereon a circle of diffused light of appreciable size, a size
also proportionate to the distance of the apex of the cone from the
film. In order, therefore, that there may be a reasonable depth of
focus and sharpness of image, the focal length of the lens must be
short. This necessity is not avoided by using larger film.
The average focal length used for general purposes is 50-mm. or 2
inches. Shorter focal lengths are frequently used, for instance !3/8
inches; but the ability of most lenses to cover a 1-inch field at a
20 degree semiangular opening with sufficient sharpness is partly due
to the absolute decrease in the dimensions of the marginal imagery
40 H. S. NEWCOMER [J. S. M. P. E.
errors. A 2-inch lens covering a 1-inch field has a semiangular open-
ing of 14 degrees. A discussion of the characteristics of the images
formed by such lenses will serve to set forth the conditions under
which motion picture lenses operate.
TYPES OF MOTION PICTURE LENSES
It has not been an easy problem to design lenses that will give satis-
factory results under the conditions obtaining in motion picture
photography. W. Merte1 discusses briefly the difficulties with which
the designer of such objectives is faced. One of the methods of
approach to the problem is to modify the Petzval objective so as to
flatten its field. As is well known, this objective in its original
form has a large aperture and an unusually sharp central definition
for a lens of such simple construction. The definition, however,
rapidly falls off and is unsatisfactory even for short focal lengths at
the margin of a field subtending a greater semiangular opening than
about 7 degrees, requiring thus a 4-inch lens to cover a standard
frame. (See Fig. 6, Solex and Cinephor.)
A second modification is obtained by placing a strong collective
element in front of or behind suitably designed Taylor triplets.
See, for instance, the Ernostar (Merte No. 10/8) and the Astro-Tachar
(Merte No. 11/8).
A third modification, semisymmetrical in type, is based on the old
Rudolph Planar which, in turn, was developed after Alvan Clark's
lens of 1889 (U. S. Pat. No. 399,499). Each half has a strong collec-
tive element in front of a compound dispersive element. Examples
of this are seen in the Xenon, Ray tar, Biotar (Merte No. 14/8) and the
Makro-Plasmat.
Another type is derived from a symmetrical lens by introducing
into each half a dispersive meniscus turned convex toward the
diaphragm (Merte No. 7/8). Such lenses having large apertures
have been widely used for amateur photography, but they cover
only a small field and show considerable spherical aberration. -
Another class of objectives deserving mention are those triplets
that have been redesigned to increase the opening to//3.5 or more.
Examples are the Hypar (similar to Merte No. 11/3) and, particularly
because of its wide angle, the Tessar (Merte Nos. 12/4, 13/4).
The quality and suitability of any of these lenses is in part de-
pendent upon the curvatures of their focal surfaces, their spherical
aberrations and their sine condition errors. All these characteristics,
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 41
for a great many lenses, are individually set forth in graphic form
in Merte's work above referred to. Whereas the graphs for the
various lenses show differences that must be associated with varia-
tions in their image-forming characteristics, these differences, as
between the more important examples, are of less significance to lens
performance than other features more readily recognized on direct
examination.
In order to bring out the limitations of all these lenses and to show
to what extent they are being utilized to their maximum capacity,
a short description of their individual and relative performance
characteristics may be made.
QUANTITATIVE ANALYSIS OF MOTION PICTURE LENS IMAGES
Figs. 6 and 7 show two sets of curves illustrating the operating
characteristics of a number of the more important motion picture
lenses. Fig. 6 shows the form of the two focal surfaces, tangential
and sagittal as they are called, of four photographic lenses and four
projection lenses. These measurements were made on a suitable
optical bench with a cross slide, using a simple ocular to locate, on a
finely ground glass mounted on a vernier slide, the best focus for
tangential and radial (sagittal) lines of the target, at different angles
of the target away from and at right angles to the axis of the lens.
In the case of the camera lenses, 2- or 3-inch lenses were used for the
measurements. The curves show where, with respect to the focal
plane, the best focus for the two sets of lines is obtained. The
sagittal surface generally lies nearer the lens. In the illustration, in
each instance, the respective surfaces are indicated by the letters S
and T. The unit "one" is chosen as one one-hundredth part of the
focal length. A certain approximation of the two curves to each other
and to the focal plane is necessary for good definition, but the exis-
tence of such an approximation does not, unfortunately, necessarily
mean that there is good definition. Thus, on the one hand, the
quality of the image on the surface may be poor; or, on the other
hand, there may be a fairly good image at some distance from the
surface. A comparison of the curves of Fig. 6 with those for blurring
of the image (Fig. 7) will show a correlation between the two, but
the latter curves more accurately indicate the quality of the image
on the film.
Fig. 7 plots for each lens described the approximate blurring of the
image, or the size of the diffusion circle in hundredths of a millimeter
42
H. S. NEWCOMER
[J. S. M. P. E.
for 50-mm. lenses, //2.3 opening (except Tessar f/2.7) at various
semiangular fields. The sizes of the diffusion circles are estimated
from inspection, under suitable magnification, of images of bold-
faced type on fine-grain negatives. In general, a block-faced letter
must be a little over 2l/2 times the height of the estimated diffusion
circle to be legible, although words are legible at somewhat less
height. Illegibility may be due to a number of imagery defects.
Thus, there may be mostly simple diffusion of the image as with the
20
20'
-1
FIG. 6. Sagittal and tangential focal surfaces of four motion
picture camera lenses and four projection lenses. Ordinates are
semiangular field; abscissas Vioo focal length.
Xenon or Ray tar; or marked astigmatism may account for the
illegibility, as in the case of the Biotar and Tessar intermediate zone
deterioration.
The curves of Fig. 7 serve to help one to visualize the more par-
ticular description of the following paragraphs, and also to correlate
information contained therein with the conditions obtaining on
projection of the image on the screen, a problem to be discussed
later.
Jan., 1933]
WIDE SCREEN PHOTOGRAPHY
43
kThe following information is based on the microscopic examination
fine-grain Eastman No. 40 and Wratten and Wainwright pan-
chromatic emulsion test chart plates, Mazda lighting, using posterior
and anterior targets to control the focal plane setting of 2-inch lenses.
Valuable additional information was obtained by the direct micro-
scopic examination of free aerial images using microscope objectives
of sufficient aperture to take in the entire cone of light traversing the
lens aperture and forming the image. This latter method enables
fe
\_^z
c\J
15" 2.0" ab
field, standard
film
FIG. 7. Curves for five 2-inch motion picture lenses
and for the corresponding maximum increment of diffusion
due to the simultaneous use of an anamorphoser of the
type described. The lateral edges of the image fields of
standard and wide film are indicated. Ordinates are dif-
fusion circles in Vioo-mm. ; standard as described.
one instantly to appraise the image quality and to determine ab-
solutely the performance characteristics at the center of the field
and the performance possibilities for nonaxial points without, how-
ever, determining whether a good lateral image actually lies in the
Gaussian plane. The method is, of course, most productive for
those who are in the habit of critically examining microscope images.
The Tessar f/2.7 is an example of a large aperture lens with con-
siderable covering power. The 50-mm. lens image is fairly sharp
at the edge of a 44-mm. area, 24-degree semiangular field. At these
44 H. S. NEWCOMER [J. S. M. p. E.
large openings, the definition of the central and intermediate areas
is relatively much poorer than with certain other types of lenses.
In fact, in an intermediate zone from 12y2 to 20 degrees there is a
distinct astigmatic blurring of the image even at appreciably smaller
openings. The images are slightly better on Eastman No. 40 emul-
sion than on panchromatic stock. As the Tessar is stopped down to
f/4.5, it loses some of its relative superiority as a wide-angle lens.
Thus, the Xenon gives a much sharper image everywhere up to about
20 degrees. The very slightly greater sharpness of the Raytar at
large angles is a stopping-down effect accompanied by decreased
illumination. With smaller stops (//4.5) the sharpness of the mar-
ginal image increases and the illumination becomes more uniform.
At//2.7 the Xenon is quite sharp for a central area of about 11
degrees semiangle; and at f/3.2 it has nearly reached the limit of
resolving power of the emulsion, and leaves little room for further
improvement. Even stopping it to //8, for instance, extends this
area of extreme sharpness only to 15 degrees, and without much
change over f/3.2. The Tessar at //8, while not so sharp in this
region, is distinctly better to the edge of a much larger field, i. e.,
beyond about 18 degrees.
The Biotarf/lA is one of the better wide aperture lenses, although
it does not give images of the quality here under discussion until
stopped down to apertures equivalent to those of other available
lenses. At f/2 or //2.3, the Xenon is somewhat sharper over the
central area and is quite good to about 15 degrees, whereas the
Biotar falls off much more rapidly beyond 10 degrees but improves
again beyond 15 degrees to be better for a narrow peripheral zone.
As the stop is decreased to //4.5 and smaller, the Biotar maintains
its wide angle superiority and becomes equal to the best lenses at
the center. The Biotar gives slightly better images on No. 40 emul-
sion, but the difference does not amount to more than one stop
(//2.3 to//2.7).
A further idea of the relative sharpness of the images of these
lenses can be had by reference to Fig. 7. In this connection it should
be noted that, for instance, the Astro Pan-Tachar f/2.3 is a very
popular lens for motion picture work, perhaps because it lacks a
certain degree of sharpness, even at the center, so that there is less
difference across the field. The fields of both the Biotar and the
Astro Pan-Tachar cut off sharply at about 22 degrees, whereas the
Makro-Plasmat has a very wide field without, however, as good defini-
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 45
tion at the larger angles, beyond 6 degrees, as even the Astro Pan-
Tachar. The Makro-Plasmat, when stopped down to //4.5, has
excellent central images up to about a 7-degree demiangular opening.
Both the new Raytar f/2.3 and the Xenon are representatives of a
type of lens that permits the attainment of high speed with excellent
definition. Good specimens of either lens in 50-mm. focal lengths
and//2.3 opening will image distinctly in the visible spectrum over a
semiangular field of 5 degrees a one four-hundredth millimeter break
in a black line of the same width. At 10 degrees, they have about
one-half and at 15 degrees one-fifth this resolving power. At the
center it is nearly twice as great. By way of comparison the resolving
power in the central area of the Astro Pan-Tachar as viewed in the
microscope is hardly one-third that of these lenses.
In this discussion of image quality, perfect definition as judged by
the microscope corresponds closely to the maximum observed sharp-
ness of the target image on the plate, and such pictures when pro-
jected with suitable lenses, even in large theaters, show extremely
good definition. When the images are less sharp, the difference is
noticeable on the screen; but if the lighting of the object is such as
to give "brilliance" to the image, less sharp definition nevertheless
gives perfectly satisfactory images. Thus the Astro Pan-Tachar, at
f/2.3 with suitable lighting, gives brilliant images with, however, an
observable deterioration toward the border to a critical eye.
LIMITS OF THE IMAGE FIELD
The rate of deterioration of the images with angle is for many of
these lenses such as to make the images unsatisfactory when the
angle is more than 10 or 12 degrees unless the focus is very short.
The maximum field satisfactorily covered by short focus wide aper-
ture lenses is 22 degrees, (28 millimeters at a focal length of 35 milli-
meters), and then only with a certain loss of quality which is notice-
able on projection if details are to be pictured.
When the focal length is increased to 50 millimeters, the standard
movietone frame has a horizontal semiangular field of about 11V2
degrees, which is about the limit to which most lenses still give
sufficiently good marginal definition not to detract from the quality
of the picture. The best lenses will cover satisfactorily somewhat
more than this, but even on the new 50-mm. wide film the angle is
5Y2 degrees greater, and then the lenses available are either appreci-
ably poorer at the border or show an intermediate zone of blurring.
46 H. S. NEWCOMER [j. S. M. P. E.
The old 70-mm. wide film carries the field clear out to 25 degrees;
and it is obvious from the data given here, as well as from practical
experience with such film, that no lens covers this field with anything
approaching the definition attained with standard film.
Thus, a careful study of the properties of the principal sharply
imaging motion picture lenses not only shows their individual points
of superiority and the absence of a "universal" lens, but makes it
quite clear that definition to the degree now attained with standard
film can not be attained on substantially larger areas if equal lens
speeds are to be used. On the other hand, wider pictures can be
optically compressed satisfactorily into the area in which good images
are obtainable.
Several wide film pictures were shown in 1930. Opinions as to the
sharpness of the images in these pictures vary with the interest and
attention of the observer and with his skill in taking account of de-
tail and contrast as they affect apparent definition. Clever com-
position and lighting play an important role in the appearance of such
pictures. Certain of the wide film pictures shown were very objec-
tionally lacking in portrayal of detail. They all showed distinct loss
of definition in the outer portions of the picture.
It seems hardly necessary to mention here the very poor results
obtainable when wide screen pictures are attempted when using re-
duced film images of modified shape blocked out on standard film.
Here, as was amply demonstrated in 1930 and as could have been
foreseen, projection difficulties are insurmountable.
THE PROJECTION LENS, ITS THEORETICAL AND PRACTICAL LIMITATIONS
When it comes to projection the same or greater difficulties present
themselves. The focal lengths are longer, 4 to 7 inches, and in order
to obtain, with a suitable aperture, the required high degree of central
definition needed for such long focal lengths, it is necessary to use
lenses of the Petzval type having notoriously limited angular fields.
The greatest volume of light is probably confined to an//3 projection
aperture, and with such an opening the central images of the best
Petzval lenses are on direct visual examination somewhat less sharp
but approximately the same as those of the motion picture lenses just
described.
The actual sizes of the diffusion circles of the Petzval lens have
been the subject of exhaustive mathematical analysis. In fact,
it would not be proper to leave this subject without reference to the
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 47
classical paper by K. Schwarzschild on the astrophotographic objec-
tive.2 Such an objective may be defined as one in which the area
to be sharply covered is not greater than the diameter of the objec-
tive, a condition that holds in motion picture photography and
projection with lenses of 3-inch focus and longer. Taking account
of third order terms, Schwarzschild gives a complete mathematical
analysis of the resolving powers of such lenses and evaluates the
theoretical minimum attainable diffusion of their images.
As is well known, the expansions of expressions for the aberrations
of spherical objectives contain only odd order terms, and it has not
yet been possible to derive solutions in which fifth or higher order
terms are retained. Probably such derivations are beyond the
capacity of the human mind. They seem to be unnecessary when cer-
tain restrictions on aperture and curvature of glass surfaces are made.
The motion picture lenses of larger aperture, having, as some or all
of them do, large curvatures of the glass surfaces, represent empirical
solutions of the problem controlled by laborious trigonometric cal-
culations. While generalizations should not be made, it is probable
that the more or less uniformity in the marginal image defects shown
by the best of these lenses is an expression of the minimal expectable
residuum of third and fifth order aberrations. Thus, where large
openings and a high degree of central definition are required, the
further addition of surfaces has, as we have seen, reduced the aberra-
tions outside the axis so as to extend the field slightly and at the
same time give the advantage of increased openings with practical
limits of about //2. 3. (Compare for instance, in Fig. 6, the first three
lenses in the second line with the other lenses.)
Every useful objective must be achromatic, i. e., color corrected
for two particular wavelengths. The residual lack of color correc-
tion for the intervening wavelengths is called the secondary spectrum
of the lens, and in the useful spectral interval reaches a maximum at a
certain wavelength. This color error of the astrophotographic objec-
tive is for the center of the field the worst error that it has; and
however small other errors may be, they will be hidden in the color
diffusion circle. The latter, therefore, even if somewhat better
tolerated, furnishes a criterion for the measurement of other errors.
Schwarzschild has shown that this color error has a minimum theoreti-
cal value, which may be expressed in terms of the size of the resulting
diffusion circle in the focal plane of the objective, this circle sub-
tending an arc of 33" v, where v is the diameter of the lens opening,
48 H. S. NEWCOMER [J. S. M. P. E.
with a diameter of //10 taken as unity. For a narrow spectral range,
as in projection, this figure can be at least halved.
It is hardly necessary to mention that objectives comprised of
thin unspaced glasses, as in telescopes, show considerable astigmatism
and curvature of the image fields. In fact if g represents the semi-
angular opening of the image field, with 3 degrees taken as unity,
then the two diameters of the diffusion circle of such lenses are
104" g*v and 47" g*v, respectively.
By separation of the elements, curvature of the field and coma can
be eliminated; and if one adheres to the Petzval type, the greatest
theoretical reduction in the diffusion circle due to astigmatism is
to 9" g^u. When we come to build such lenses, 12" g^u seems to be
the practical lower limit. The lenses have, however, the theoretical
lower limit for the secondary spectrum, namely, 33" v.
In Fig. 6 are shown the positions of the tangential and sagittal
image surfaces of two types of Petzval lenses. The Cinephor was
selected for this discussion because it is an example of the most com-
mon type of Petzval construction in projection lenses. It has con-
siderable astigmatism, but the average curvature of the field is not far
from zero. A drawing is included of a Cinephor of later manufacture
having, up to nearly 5 degrees, no astigmatism and a very flat field.
Another type is illustrated by the Solex lens. The Solex, although
having an appreciable curvature of field beyond 5 degrees, up to
that point has little curvature and less astigmatism and gives ex-
cellent images with standard film in the usual focal lengths.
In all instances curves for 41/2-inch projection lenses are given. In
motion picture projection, the size of the field to be projected remains
constant regardless of the focal length of the lens; hence the de-
signers of projection lenses have been under no obligation to make all
focal lengths geometrically similar, such as is generally done in the
case of ordinary photographic lenses where plate size is proportional
to focal length. The values given for the Solex and Cinephor, there-
fore, can not be regarded as strictly applicable to all lenses bearing
those names, although they give a correct impression as to their
characteristics. Likewise, the focal surface characteristics of cer-
tain motion picture camera lenses vary with the focal length.
The Taylor type of objective, with three spaced elements and some-
what greater curvatures of the glass surfaces, can be designed with
appreciably smaller diffusion circles due to astigmatism, but the
secondary spectrum increases to about 51 "v.
Jan., 1933] WIDE SCREEN PHOTOGRAPHY 49
Let us now evaluate these expressions. A 4V2-inch projection lens
has a horizontal semiangular field on movietone film of about 5
degrees. The useful opening is probably not over //3.3. Thus
v is 3, g is 1.67, gz is 2.8, and g*v is 8.4. The lens being of the Petzval
type, its diffusion circle at the margin is about 100 seconds or 0.055
millimeter. Its color diffusion circle at the center is probably about
10" 'v or 0.017 millimeter. Both these figures correspond very well
to the observed tolerances and direct observation on good lenses.
The figure for the margin is usually a little larger.
The result of projection is then to deteriorate still further, but
to an unimportant extent, the central image. The legibility of de-
tails in the projected image is within the tolerances to be discussed.
The deterioration of the marginal image of the standard frame is of
more consequence, but is still just allowable. If, however, a Petzval
lens were used to cover the frame of 50-mm. wide film, g2 becomes
three times as large and the marginal diffusion circle is 0.165 milli-
meter. As we shall see, this is too large. To project such pictures,
other lenses must be used. Unfortunately, it is not easy to find a
substitute. The use of an anamorphoser is a much simpler solution.
DEFINITION ON THE SCREEN; PHYSIOLOGICAL REQUIREMENTS
CORRELATED WITH LENS PERFORMANCE
We should now consider these numerical data in the light of the
observed image on the screen. The center of a sharp motion picture
negative or positive will show distinctly letters formed by lines
0.01 to 0.02 millimeter wide. Letters that are 0.1 millimeter high on
the film may be nearly illegible without one's noticing loss of detail
when the picture is projected. In a theater with a 100-foot throw
and a 25-foot picture, such a letter is about 30 millimeters high on
the screen. At a distance of 40 feet from the screen, the average
person with good vision can read letters 20 millimeters high, but he
does not try to exercise his vision to this extent and can not distinguish
the coarser details of the letters until they are about 80 millimeters
high, the distinguishable details then having dimensions of about 10
millimeters.
Probably the average critical observer does not notice extreme
haziness of letters that are 0.1 millimeter high on the film. Even their
being illegible may not be noticed, so that what has here been called
a 0.04-mm. diffusion circle would be just tolerated at the center of
the picture. This size of diffusion circle would be quite satisfactory
at the border, and nearly twice that size would be tolerated provided
50 H. S. NEWCOMER [j. S. M. P. E.
projection did not make matters worse. The figure 0.055 millimeter
given above for projection is perhaps not to be added in its entirety
to the size of the diffusion circle at the margin of the negative image
(Fig. 6) but the combined effect must be just about what has been
considered allowable.
In order to visualize the meaning of these figures one might hold
an inside page of the" New York Times at arms length. The "want
ads" will be just legible. The individual letters, even if jumbled,
would also be legible if they were distinctly formed. Such letters
correspond to the 20-mm. screen letters of the above example or to
0.07-mm. film letters. Even the very best lenses will not reproduce
such characters sharply; and, indeed, the reader in looking over the
newspaper at arms length does not attempt to notice print of that
size. He is not even attentive to the ordinary newsprint, which is
half again as large. On the other hand, letters 40 millimeters high
on the screen — 0.14 millimeter on the film, for which our diffusion
circle is 0.05 millimeter — correspond to minor titles in the news
column, which may very well be read if the attention be attracted
to them. In sharp film they will be legible, but not as clear as in
the news print analogy. The 80-mm. screen letters, appearing sharp
or at least clear, as they do in good pictures, correspond roughly to
the column headings in the newspaper. They must appear distinct if
even the casual observer is to be satisfied. While such letters are
sharp at the center and distinct to the edge of standard film, a com-
parison with the curves of Figs. 6 and 7 shows that they would be
just about illegible in the peripheral areas of wide film no matter what
lens were used.
Anamorphosed or compressed negative motion picture images
are obtainable in actual practice in which there is perfect definition
of letters appearing even at the margin of the picture and of sizes
down to 0.14 millimeter high on the film. Such letters to be sharp
mean diffusion circles appreciably less than 0.04 millimeter on the
film. In practice, letters that are 0.04 millimeter high on the film
are illegible, the amount of illegibility fixing the diffusion circles in
the central area at about 0.02 millimeter, corresponding therefore
with the data of Fig. 7.
Referring to Fig. 6, it should be remembered that the projection
lens works at twice the focal length of the typical camera lens we
have been considering. The diffusion referable to the curvature of
the image fields shown for the Solex and Cinephor projection lenses
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 51
should be doubled when making comparisons with the data for the
camera lenses. The projection lens, however, when used on standard
film, is required to cover at most a semiangular field of only 5 degrees,
and under such conditions does fairly well. It is extremely poor at
10 degrees and useless beyond and, indeed, before 10 degrees.
Where wide angle projection is necessary, it is possible to better
the performance of the Petzval lens. Reference will not be made
here to back screen projection where both the focal length and throw
are short and the screen image less sharp than in standard practice.
We have seen that attempts to improve lenses that perform similarly to
the Petzval lens have resulted in the development of the present motion
picture camera lenses. In the case of the best motion picture lenses
above described, working at //2.3 or //2.7 for 4V2-inch focus, the
diffusion circles at the center of the image for the visible spectrum
are about 0.004 to 0.01 millimeter. Letters 0.05 millimeter high on
the film are quite legible and sharp. On the other hand, at a semi-
angular field of 8 or 10 degrees and for this focal length, the diffusion
circles are about 0.04 millimeter or more.
The Super Cinephor is an example of a camera lens, the Raytar,
adapted to projection purposes. In Fig. 6 are given the forms of its
image surfaces. (The 6" Raytar has similar but still more curved
surfaces, particularly the sagittal surface.) There is a distinct flatten-
ing at the larger angles as compared with the Petzval type lenses.
By way of comparison, the hand camera anastigmat working at
considerably smaller openings seeks to limit the diffusion at a semi-
angular field of about 30 degrees to 120 seconds. The central defini-
tion is not as good as with the lenses here under discussion. Great
skill and effort have been expended in an endeavor to improve the
marginal definition of all of these lenses. The limits reached are
fairly well defined and the underlying mathematical concepts do not
offer much encouragement that the results already achieved will be
much extended.
It has been shown that it is not possible to take, nor is it feasible
to project, wide screen pictures under conditions that will result
in images half as good as those now obtained. On the other hand,
wide screen pictures of a quality comparable with the present stand-
ard pictures may be obtained by using an anamorphoser. The
simplicity of this method of projecting wide screen pictures hardly
needs to be elaborated upon. One further advantage of the anamor-
phoser should, however, be mentioned. This is an optical advantage.
52 H. S. NEWCOMER [J. S. M. P. E.
increasing the depth of focus, and hence the general sharpness of the
images, over and above that of ordinary pictures.
THE CYLINDRICAL ANAMORPHOSER INCREASES DEPTH OF FOCUS
A cylindrical anamorphosing system magnifying 50 per cent in one
meridian increases the depth of focus in that meridian by 100 per cent.
If the anamorphoser be focused for a given object distance, then the
interaction of the two elements of the anamorphoser on light com-
ing from points nearer and further away is such as to approximate the
corresponding camera lens images and bring them nearer the image
plane for the mean focus. The amount they are moved toward
this plane is exactly one-half the focusing difference for the camera
lens.
For reasons associated with the nature of image formation in the
eye, the effect of natural diagonal astigmatism, the apparent gain
in depth of focus is practically equivalent to these figures. In fact,
all who have studied anamorphosed wide screen pictures have noticed
this effect. Similarly, for physiological reasons, the expansion in
one meridian only does not increase the graininess of the projected
image. The pictures are as smooth and free from graininess as un-
expanded pictures two-thirds the size.
Up to this point we have considered only the quality of the image
in the plane of best focus. Nothing has been said as to the loss of
definition due to the photographing of portions of the object lying in
front of or behind the plane of sharpest focus.
The following table gives the focal distances for a certain series
of lenses when the object is at 15, 20, and 25 feet. The last two
lines of the table give the focal differences with respect to the mean
image for the 20-foot distant object.
Focal Distances of a Lens Series
(Millimeters')
Object
Distance
(Feet)
50
75
100
125
150
15
50.553
76.251
102.236
128.513
155.09
20
50.413
75.935
101.67
127.616
153.8
25
50.33
75.74
101.33
127.084
153.01
diff. in
0.14
0.316
0.57
0.897
1.29
diff. out 0.08 0.20 0.30 0.532 0.8
The relative openings being the same in each case, the sizes of the
diffusion circles, due to distances out of focus, of the objects in front
Jan., 1933] WlDE SCREEN PHOTOGRAPHY 53
and back of the sharply imaged object are directly proportional to
these distances. Thus, if the focal length of the lens be doubled,
the figures show that the loss of definition due to decreased depth of
focus is increased four times.
Consider the deterioration of the image of a 50-mm. lens due to
depth in the object, as given in the example. For the lesser of the
two differences it amounts to a diffusion circle of 0.04 millimeter.
Diffusion circles this large (and many are even larger) all over the
film area cause the quality of the picture to deteriorate to an appreci-
able extent. The anamorphoser reduces these diffusion circles to
half, and does much to improve the actual operating quality of the
image and bring it within figures comparable with those given for the
plane of best focus, as for instance in the data of Fig. 7.
For cameras, combination motion picture lens and anamorphoser
mounts make focusing a single operation, as simple as in ordinary
practice. For the theater, a simple fixed mount can be devised which
reduces both costs and adjustments, and permits rough handling.
Orientation of the anamorphoser in the proper meridian is so simple
that any child could accomplish it.
Thus, the optical and practical advantages of the anamorphoser are
real and important. Its use will greatly facilitate the introduction
of wide screen pictures with their many advantages for improved
pictorial effect, pleasing proportions, and increased number of full-
length characters on the screen. In the latter case, the increase in
size of the object imaged, an increase allowed by the altered propor-
tions of the frame, still further increases the apparent sharpness of
the picture. This effect can not be ignored, particularly in color
photography, where there is a certain inherent lack of definition that
this application of the anamorphoser will overcome, and without
interfering with the technic of the color process.
REFERENCES
1 MERTE, W.: "Construction Types of Photographic Objectives," Handbuch
der Wissenschaftlichen und Angewandten Photographic (Vol. I, The Photographic
Objective), Vienna (1932), p. 243.
2 Abhand d. Koniglichen Gesellschaft d. Wissenschaften zu Gottingen. Math.
Phys. Klasse, New Series, IV (1905), No. 3.
PHOTOGRAPHIC EFFECTS OBTAINED WITH INFRA
D NEGATIVE*
D. R. WHITE**
Summary. — The characteristics of Infra D film, a stock designed specifically for
specialized cinematography, possessing distinctive spectral sensitivity, are described.
The sensitivity is limited to two regions at opposite ends of the spectrum, a relatively
wide gap occurring between. Examples of the use of the film in producing special
pictorial effects are given in the illustrations.
Infra D film is a stock specially designed to meet the requirements
of some of the specialized work of cinematographers. Its widest use
is in the simulation of moonlight effects, but it has also been used for
taking pictures through aerial haze.
The utility and special properties of this film are based funda-
mentally upon its distinctive spectral sensitivity. Fig. l(a) shows
that this sensitivity is effectively restricted to two regions at opposite
ends of the visible spectrum with a relatively wide gap between.
The film is, therefore, "green blind," so that it can not be used where
true reproduction of visual brightness values is desired.
The sensitometric characteristics of Infra D are shown by the
curves of Figs. 2 and 3. These curves resulted from rocked tray
developments, in borax developer, of the film as exposed in a non-
intermittent time scale sensitometer, in which the light source was an
unscreened incandescent lamp operated at a color temperature of
2475° K. The crosses of Fig. 3 give time-gamma values for du Pont
special panchromatic negative processed with the Infra D, and show
that the two stocks are very similar in their development behavior.
Thus, the Infra D introduces no new processing difficulties, and can
be handled along with other negatives.
Further information concerning its sensitometric characteristics
and its spectral sensitivity is contained in the group of curves of Fig.
4 and the spectrograms of Fig. 1. The spectrograms made through
the filters were not all exposed for the same time, but the times were
* Received by the editor Oct. 24, 1932.
** Du Pont Film Mfg. Co., Parlin, N. J.
54
INFRA D NEGATIVE EFFECTS
55
adjusted to agree partially with the increased exposure that would be
required in practice and to emphasize pictorially the effective spectral
regions. The sensitometer lamp was screened in turn by each of the
series of filters used in making the spectrogram and, in addition,
with the Wratten green or B filter. The spectrograms show the
(f)
FIG. 1. Spectrograms on Infra D film, exposed to
incandescent light unscreened and screened by various
Wratten niters: a, unscreened; b, K3 filter; c, A filter;
d, F filter; e, 70 filter; f, 88 filter.
nature of the light that was effective through each of the filters,
and the curves show s'ensitometric characteristics of the film as
exposed to that light. The relative placing of the curves along the
log E axis is related to the filter factors for the various filters with
that illumination, the displacement, in logarithmic units, of any
curve from the white light curve being the logarithm of its filter
56
D. R. WHITE
[J. S. M. P. E.
factor. The extreme displacement of the curve with the green or
Wratten B filter emphasizes again the low green-sensitivity of the
film. The gamma value obtained with the film depends upon the
05
FIG. 2. H & D curves for different development times
on Infra D film.
character of the light incident upon it, being greater for red than for
white light.
The increased contrast resulting from red light exposure can be
1.2
0.8
o.i
Gamma
Dty Time- Mm.
u 2 4 6 8 '0 iz
FIG. 3. Time gamma curve for Infra D film. Borax
developer was used, rocked in a tray. The crosses show
gamma values from du Pont special panchromatic
negative developed at the same time.
put to very practical use in photographing through haze, when
sufficient exposure can be given. The red filter aids in obtaining
detail through the haze, the greater contrast also increasing its
Jan., 1933]
INFRA D NEGATIVE EFFECTS
57
visibility in the finished picture. Fig. 5 shows two pictures taken
from an elevated point of land looking over miles of lowland on a
day when haze was noticeably present. The rendering of detail in
the picture taken through the red filter far surpasses that of the
FIG. 4. H & D curves of Infra D film exposed to white
light and to light screened by the various Wratten filters
indicated.
picture taken with no filter; and, in fact, surpasses that of other
test pictures made at the time using different filters and different
types of film. The greater detail is due both to the penetration
FIG. 5. Pictures taken from an elevated point of land: left, no filter on
panchromatic film; right, 70 filter on Infra D.
of the red light through the hazy atmosphere and to the greater
contrast of the film due to the fact that the latter was exposed to red
light.
The photographs shown in Fig. 6 (a, b) and Fig. 7 are pictorial
58 D. R. WHITE [j. S. M. P. E.
in character, intended to typify some of the possibilities of the stock
and to show the results to be expected from some of the filters fre-
quently used with it.
FIG. 6 (a). FIG. 6(b).
FIG. 6. Pictures taken on Infra D film in bright sunlight on a July afternoon,
printed on the same grade of paper: (a) no filter; (b) F filter. A K3 filter pro-
duces an appearance intermediate between those of (a) and (b); A, 70 and 88
filters produce effects somewhat similar to those of (b) when the proper filter
factors are used.
FIG. 7. Picture made from same negative as those of
Fig. 6, but with different technic, particularly in the
printing and selection of paper.
The filter factors, in bright sunlight, are given in the table below:
Filter Factor
Kt 16
A 64
F 64
70 64
88 90
Jan., 1933] INFRA D NEGATIVE EFFECTS 59
These were used in obtaining the pictures shown, and are designed
to give pictures of very similar overall density. The pictures, Fig.
6 (a, b), were both printed on the same grade of paper, and show the
relative changes produced by the niters. The pictures were taken
on a bright July afternoon, but those taken with red niters, of which
6(b) is typical, resemble snow scenes as they are printed. Fig. 7
resulted from printing the negative used for Fig. 6(b) on a softer
grade of paper; resulting, in this case, in quite a satisfactory night
picture. It is sometimes desirable somewhat to underexpose such
pictures in order to suppress shadow detail, or to underdevelop the
negatives slightly so as to obtain the desired effect. The extent to
which these methods are used depends upon the final effect desired.
The dark sky and sharply defined shadows of night can be thus
simulated in bright sunlight. Care must be used to have the rest of
the atmosphere correct, of course, since windows and streetlights
are often lighted at night but rarely in the daytime, and omission
of these details might be fatal to the effect.
The limits of the use of this stock have by no means been reached.
Trial and study by the users of the film will surely lead to unique and
beautiful effects not touched on here.
REMARKS ON THE MAKING OF SOUND RECORDS
ON LENTICULAR COLOR FILMS
A. P. RICHARD*
Summary. — Several precautions must be observed when variable density sound
records are produced on 35-mm. lenticular film. An ammoniacal glycine solution
is considered the most satisfactory developer. In order to secure the necessary indi-
vidual control of the picture and sound records, it is suggested that the picture record
be developed in a devoloper sufficiently charged with bromide, reversed, and then
bleached, cleared, and dried. The sound record should then be exposed on the
slightly sensitive emulsion remaining, and the entire film then developed, fixed,
washed, and dried.
For better sound reproduction it is also suggested that the height of the embossed
lines in the sound track area be less than that in the picture area.
In considering the future of motion pictures in color, with the so-
called lenticular films, it appears probable that their introduction
into the industry will demand certain precautions. From an optical
point of view it should be possible to avoid the reversal process, but
at present it is necessary to use this method.
In the opinion of the writer, the application of the process to 35-mm.
film would benefit by the use of CapstarFs methods with respect to
the second exposure1 since the reversal process using a solvent de-
veloper is a difficult one which requires control in the second ex-
posure and development.
If a reversed image in colors be made in silver bromide, the gamma
can easily be measured, and it appears that the development of the
second exposure to gamma infinity does not always give the best
colored image.
The loss of color in the reproduction, as compared with the original,
can be put at approximately 15 per cent of the quality and the ac-
curacy of the subject. Attention is called to the fact that an original
on 35-mm. lenticular film has never, in the writer's experience, been
made according to Capstaff's methods.** We may, therefore, infer
* Technical Director, Tobis Sound Films, Paris, France.
** Since the preparation of this article, such films have been projected before
the Society.
60
SOUND RECORDS ON LENTICULAR FILMS 61
it in the majority of cases the original that was to be reproduced
was not the best one that could be obtained.
A striking example can be found by considering the scales of blue
and red colors. It is clear that the curve after the second develop-
ment does not differentiate between a deep navy blue and black, and
that the maximum density between black and blue varies within very
narrow limits.
On the other hand, in reproduction, the "antidiffusing power"
of the developer that is used for the first development must be taken
into account. The "antidiffusing power" of a developer is a func-
tion of its reduction potential. The lower the reduction potential
the less is the "diffusion," and the better is the definition. Hundreds
of tests have shown that the ammoniacal glycine developer (Richard's
formula) is one of the best for the lenticular process, since glycine has
in this developer a very low potential, which approaches the desired
value.
By photographing a white surface with lenticular film and using
the reversal process, a film is produced in which the centers of the
fields behind the lenticular elements are clear and the interspaces are
black. If a silver salt be precipitated in the gelatin layer of this
film, an emulsion of very fine grain with artificially darkened inter-
spaces is produced. After the exposure of such a film in the camera it
is possible to develop without reversal by means of an amidol de-
veloper and thus to produce a negative image in brilliant colors,
demonstrating the role played by "diffusion."
The best developer is made according to the Lippman formula,
which is used for interferential photography; but this formula can not
be recommended owing to its tendency to form dichroic fog.
The preventing of moire* pattern in optical printing does not result
in the same sharpness as is obtained in contact printing. It is
necessary to accept a much lower degree of sharpness, which in-
fluences equally the rendition of the tricolor selection filter by each
element. It is therefore obvious that it is very important to do
everything possible to prevent "diffusion" from exerting a serious
effect.
In making sound films by means of these processes, the above
must be borne in mind because the sensitometry of reversed films
with a solvent developer shows that industrial practice is attended
by unexpected difficulties. These difficulties are, moreover, still
more noticeable with solvent ammoniacal developers.
62
A. P. RICHARD
[J. S. M. p. E.
Very satisfactory definition can be attained by means of lithia
and ferrocyanide combined with eikonogen and pyrocatechin B,
but the colors are not as brilliant as they are when ammoniacal glycine
is used, for instance. This developer without ammonia has certain
advantages from the sensitometric point of view, but its "diffusing"
action, although less than that of many others, is still too great to
make it useful, especially when reproduction is concerned (Bonnerot
& Richard, 1926).
To return to the sound film, it is well known that the printing
FIG. 1. Illustrating the embossings in the sound track
area of the film. (Film 2 X natural size ; corrugations 90 X
natural size.)
necessitates certain precautions; the condition jn X JP = (K)
should be satisfied completely.* As in the Western Electric movie-
tone or the Tobis-Klangfilm processes, the average density varies
between approximately 0.35 and 0.5.
If the sound be recorded on the margin set aside for the purpose,
at the time of printing the picture, and the film be developed by
reversal according to the known process, irregular results will be
* 7n = negative gamma; yp = positive gamma; K = constant.
Jan., 1933] SOUND RECORDS ON LENTICULAR FILMS 63
obtained because nearly always one factor must be sacrificed for the
benefit of the other.
While in this respect the variable width methods are much more
flexible, the first development must be continued to such a point that
after reversal the white spaces are perfectly clear; it being under-
stood that the solvent reducing function has been perfectly balanced.
These considerations lead to the conclusion that the sound printing is
uncertain under these conditions and subject to all kinds of restric-
tions. The following method solves the problem.
The image is developed by the usual solvent reducing method, the
developer being charged sufficiently with bromide. The image is
reversed in permanganate ; or better, in potassium dichromate, owing
to its tanning action. The bleaching and clearing in sulfite at the
beginning of the washing should take place in nonactinic yellow
light. After this operation, the drying is carried out in a room
illuminated with yellow light. The result is a positive in silver bro-
mide where the margin has been set aside for the sound record.' In
printing, it should be remembered that the emulsion has lost its
speed, owing to the destruction of the sensitivity centers of the emul-
sion grains.
The image is exposed again, giving it the necessary exposure for
obtaining the best result. We then have a reexposed positive pic-
ture image, a positive sound record in the latent image state, and a
developer whose characteristics at an average temperature of 18°C.
are known.
It is then easy to obtain a sound positive in colors of high quality
by development in an ordinary developer, the only necessary pre-
caution being to choose a developer that deposits reduced silver of a
color as nearly neutral as possible. After fixing and washing, the
final result is obtained.
By means of the process described, it is possible to calculate in
advance the exposure time necessary for the sound and the picture
in order that the sound may satisfy the sensitometric conditions that
give the best results.
When a lenticular sound film is reproduced, it is noticed that the
high frequencies are not rendered with great fidelity. The loss of
audibility is not very great, but it is sufficient to be noticeable to a
technician. Hence, the sound margin should be left smooth when
the film is embossed (Pathe-Kodak patent) . A different procedure
can also be adopted by making a less pronounced embossing on the
64 A. P. RICHARD
margin, the direction of the lines being perpendicular to the slit*
(Fig. 1).
The conditions for projection are identical to those of a film with a
smooth margin, and no appreciable difference between the sound
reproduced from a film with a smooth margin and the sound from
film with a corrugated margin can be noticed by this method. More-
over, the advantage of the horizontal corrugation is retained for
the picture, and additional frequencies are prevented from entering
into the sound band that would otherwise increase the ground noise.
REFERENCES
1 U. S. Pat. 1,460,703, July 3, 1923; also U. S. Pat. 1,552,791, Sept. 8, 1925.
* It should be noted that the embossings in Fig. 1 have been drawn on a greatly
magnified scale compared with the film.
MAKING A FADE-OUT BY AFTER TREATMENT*
C. E. IVES, L. E. MUEHLER, AND J. I. CRABTREE**
Summary. — Fade-outs have been made for many years by moving the diaphragm
or using a dissolving shutter in the camera during exposure. It is more convenient,
however, to make a fade on either the developed positive or negative film by chemical
means.
A modified Belitzski reducer formula of the "cutting" type is recommended for
negative fade-outs. The film is introduced into a tube or tank filled with the solution
with a positive acceleration so that the portion immersed last receives the least degree
of reduction and a wedge effect is obtained. Another method consists in bleaching
out the image in either a ferricyanide-bromide or a permanganate bleaching bath and
redeveloping with the same manipulative treatment as for reduction. Positive fade-
outs may be made conveniently by tinting with a black dye solution.
A mechanical device is described by means of which the necessary acceleration
may be imparted to the film when immersing in the various solutions.
The fade-out (and fade-in) has been used extensively to cause a
pleasingly gradual transition between successive scenes in a motion
picture, and is regarded in many cases as a necessity for the artistic
presentation of the picture story. The fade-in and fade-out are essen-
tially similar in nature although opposite in arrangement, so that
for convenience only the fade-out is referred to in this paper.
The fade-out can be defined as a process whereby the picture is
made to disappear from view by a diminution of brightness and con-
trast of the picture toward the end of a scene.
For many years fade-outs were made in the camera by decreasing
continuously the light which reached the film through the optical
system as the end of the scene was approached. Thus, as the fade-
out progressed, the negative was more and more underexposed until
at the end of the scene no image whatever was produced.
When a print is made from a negative which contains a fade-out
the printing exposure is not varied within the scene, so that the frames
included in the fade-out are progressively more dense and deficient
* Communication No. 475 from the Kodak Research Laboratories.
** Eastman Kodak Co., Rochester, N. Y.
65
66 IVES, MUEHLER, AND CRABTREE [J. S. M. P. E.
in contrast. When such a fade-out is projected on the screen, the
"fading" is seen to consist of the disappearance of, first, the shadow
detail, second the medium tones, and finally the highlights.
As the art of editing developed, it became necessary to make the
fade-out in the developed negative after the cutting process was
completed. This necessitated either the insertion of a duplicate
negative in which the fade-out was produced in the same manner as
in the camera, or the alteration, by chemical treatment, of the
original negative. In the latter case photographic reducing solutions
were used to produce so-called "chemical fades."
Recently it has been considered desirable to insert fades in their
proper places in the editorially cut print so that when it is viewed
for final approval it is complete in all respects. Any cutting or altera-
tion is done in the negative after this print has been approved. A
method of making the required fades in the positive has been de-
veloped and will be described in this paper.
THE NATURE OF A FADE-OUT
The first requisite of a good fade-out is that it shall cause the
picture to disappear in a gradual and continuous manner. If it is
abrupt, or has the appearance of being discontinuous, it does not
serve the function for which it is intended. The fade-out must begin
at a certain frame and go to completion between this point and the
end of the scene. The average rate of change of density is deter-
mined by this length and the maximum density change which must
be effected. The course of the change should be such that when the
picture is viewed by projection the average brightness appears to
diminish at a uniform rate.
If the change in brightness is to appear uniform, the density of
each frame should be related to that of the next by an approximately
constant difference. This is because, in general, the eye appreciates
as equal steps of brightness those which are related to each other by
equal logarithmic differences. Since density is a logarithmic quan-
tity, equal density steps in the positive produce the desired logarith-
mic steps of image brightness on the screen. In order to produce
these equal density steps in the positive the photographic reproduc-
tion characteristic requires equal density steps in the negative over a
large part of the fade. A fade-out in which the density change
follows this course has been found satisfactory.
Jan., 1933 j MAKING FADE-OUTS BY AFTER TREATMENT
67
NEGATIVE FADE-OUTS
In order to make chemical fade-outs in a negative which are
similar in appearance to those produced in the camera, a photo-
graphic reducing solution must be employed which has the property
of altering the densities of the negative in such a way that it will
appear underexposed instead of underdeveloped. The so-called
cutting reducers are of this type, and their action is illustrated by
the curves in Fig. 1. In this figure, each curve represents the densi-
ties corresponding to a logarithmic series of exposures, as is usual for
photographic characteristic curves. Curve A shows the densities
before treatment with the reducer, and Curves B, C, and D the
densities remaining after various degrees of reduction. As the
e.o
1.8
i.e
1.4
i.i
i.o
0.4-
O.Z
FIG. 1. Curves illustrating the action of cutting reducers.
time of treatment is increased, the lower densities are removed
completely and all densities are lowered by an approximately equal
amount which gives the desired appearance of underexposure. The
data from which these curves were plotted were obtained by the use
of a modified Belitzski reducer.1
In Fig. 2 are shown curves representing the change of density in a
highlight which took place throughout the length of two camera
fades selected at random from commercial productions. These
curves show considerable differences, and the departure from a linear
change in density is rather wide. The change in highlight density
with increasing distance from the start of the fade-out is slow at first,
and finally rises to an approximately constant rate. In view of the
fact that a fade-out in which the highlight density changes at a
68
IVES, MUEHLER, AND CRABTREE
[J. S. M. P. E.
uniform rate throughout the fade has been found to have a pleasing
and perfectly normal appearance, it can be concluded that the
FIG. 2. Curves illustrating the change of density in
a highlight occurring throughout the length of two
camera fades selected at random from commercial
productions.
particular shape of the curves in Fig. 2 indicate inefficiencies, and are
merely the result of mechanical expediency.
PHOTOGRAPHIC REDUCING SOLUTIONS FOR PRODUCING FADE-OUTS
In Fig. 3 the progress of density reduction with time of treatment
using the modified Belitzski reducer is shown for a highlight area in a
negative where the original density was 0.9. The formula for this
reducer is given below.
Modified Belitzski Reducer
(Formula R-8)
Ferric alum 25 . 0 grams
Potassium citrate 75 . 0 grams
Sodium sulfite (anhydrous) 30 . 0 grams
Citric acid 20 . 0 grams
Sodium thiosulfate (hypo) 200 . 0 grams
Water to 1.0 liter
Jan., 1933] MAKING FADE-OUTS BY AFTER TREATMENT 69
The Belitzski reducer, which is more stable, is recommended in
preference to Farmer's reducer.
Farmer's reducer, as commonly used by photographers, consists
of a 10 per cent solution of hypo in which is dissolved enough potas-
sium ferricyanide to cause the reduction to proceed at the desired
rate. Alternatively, a two-bath process is sometimes used which
involves the use of a potassium ferricyanide solution of suitable
strength for the first bath and an ordinary fixing bath for the second.1
The two-bath Farmer's reducer can be kept for long periods of
time, but its use is more complicated and control is difficult. When
the two-bath formula is used, the time of treatment in the first
bath is varied to give increasing degrees of reduction from one end
of the fade to the other. All parts of the fade are then given the
same time of treatment in the second bath.
The three reducers mentioned above leave a faint stain image
which is not ordinarily objectionable. When a cutting reducer is
required which leaves no stain image, the iodine-cyanide reducer is
satisfactory, but it has the disadvantage of being very poisonous.
It consists of a solution of potassium cyanide to which a small quan-
tity of iodine has been added.
Another method of producing a fade-out which is free from stain
is to bleach the entire length of negative where the fade-out is to be
made, and then to redevelop the image to varying degrees along the
length to produce the densities required in the fade.
Either of the two bleach formulas given below is suitable for
converting the silver image to one of silver chloride or bromide.
Ferricyanide- Bromide Bleach
(Formula T-lOa)
Potassium ferricyanide 20.0 grams
Potassium bromide 5 . 0 grams
Water to make 1 . 0 liter
Permanganate Bleach
(Formula S-6)
Stock Solution A
Potassium permanganate 5.3 grams
Water to . 1.0 liter
Stock Solution B
Sodiumjchloride 75.0 grams
Sulfuric|acid* (concentrated) 16.0 cc.
Water to 1.0 liter
70
IVES, MUEHLER, AND CRABTREE [J. S. M. P. E.
For use, mix equal parts of A and B immediately before using.
The mixed bath does not keep long.
The silver chloride image can then be redeveloped to the desired
degree in a developer such as D-16* diluted to one-fourth strength,
after which the film is fixed in an ordinary fixing bath to remove the
undeveloped silver halide.
Before redevelopment is attempted, the bleached image should be
1 <b
1.4
I-Z
1-0
08
Ofe
04
100 Z.OO -&OO 400 ^00 0,00 TOO 600 ^00 tOOO
FIG. 3. Course of reduction of motion picture panchromatic type 2 negative
film in modified Belitzski reducer.
exposed to strong daylight, but not sunlight. The result of the
bleaching and redeveloping operation is equivalent to proportional
reduction, so that the camera fade is not simulated so closely.
The curve in Fig. 3 shows that the diminution of the density of a
highlight with the Belitzski formula is not strictly proportional to
the time of treatment. The shape of this curve is such, however, as
to suggest that if that portion of a negative where a fade-out is to be
* Motion Picture Film Developer
(Formula D-16)
Water (about 125 °F.) (52 °C.)
Elon
Sodium sulfite, desiccated
(E. K. Co.)
Hydroquinone
Sodium carbonate, desiccated
(E. K. Co.)
Potassium bromide
Citric acid
Potassium metabisulfite
Cold water to make
Avoirdupois
Metric
64 ounces
2.0 liters
18 grains
1 . 24 grams
5 ounces
158.4 grams
130 grains
350 grains
24.0 grams
21/2 ounces
74 . 8 grams
50
40
grains
grains
grains
gallon
3 . 44 grams
2.72 grams
6 . 0 grams
4.0 liters
Jan., 1933] MAKING FADE-OUTS BY AFTER TREATMENT
71
made were led end first at a constant rate into the reducer, a very
acceptable fade-out would be produced. This opinion is based
upon the similarity of the curve produced in this way and shown in
Fig. 4. Curve A shows the densities remaining in the highlight of a
negative treated in this manner, and Curve B shows the highlight
1.6
It.
1.4
l.fc
1.0
0.6
0.6
0.4
O.Z
10.
FIG. 4.
Reduction of motion picture panchromatic type
2 negative film.
A, negative, time of treatment proportional to distance
from end of fade-out.
B, print from A .
densities of a positive printed from it. A print including a fade-out
made in this way was examined by projection and found very satis-
factory and entirely typical.
Methods and apparatus for handling the film during a treatment of
this kind are discussed later in this paper.
POSITIVE FADE-OUTS
It is assumed that a fade-out is to be introduced into an editorial
positive print after it has been developed and when the editing is
complete. A convenient method of darkening the film so as to
simulate a fade-out is to stain the film with increasing quantities of a
neutral black dye as the end of the scene is approached. A satis-
factory method of controlling the density added in this way is to
vary the time of bathing in an aqueous solution of a dye which has an
affinity for gelatin.
No single dye having the desired properties was found, but a
combination of three dyes in the formula given below produced a
72 IVES, MUEHLER, AND CRABTREE [J. S. M. P. E.
visually neutral black with a projector low-intensity arc lamp. It
would be possible to use these dyes in slightly modified proportion
in case the spectral distribution of the light source used is somewhat
different from that mentioned. The formula can be considered
merely as a guide to the proper proportions, because various samples
of the same dyestuff are often found to differ in purity.
Visually Neutral Dye Bath
Acid anthracene brown B* 8.7 grams
Toluidine blue * * 8.7 grams
Naphthol green** 2. 6 grams
Water to make 1 . 0 liter
In deciding upon the density to be added by dyeing, preliminary
tests were made which showed that a maximum density of about 4.0
should be reached in order to obliterate the image entirely. This
density seems rather high, but is necessitated by the fact that the
contrast is not degraded by the addition of a uniform density over
the picture. It is necessary, therefore, to increase the superimposed
density to a point where even the brightest part of the image is
covered effectively. This condition is usually attained when the
added density is 4.0 because of several factors. Among these, the
following are important:
(a) Visual contrast perception is greatly reduced at a screen brightness level
equal to one ten-thousandth of the ordinary level.
(b) The adaptation level of the eye in an ordinary auditorium or theater is
usually at a level which is much higher than that which would give the best
contrast perception when the fade-out is in progress.
(c) The stray light falling on the screen is usually enough to obliterate the
image beyond a brightness level reached during the fade.
From the considerations cited previously, it was concluded that a
constant change in density with distance along the fade would be
suitable. Tests of positive fades made in this way proved satis-
factory on projection.
It was found that the density produced by the dye formula given
above was proportional approximately to an exponential of the time
of bathing, as shown by the curve in Fig. 5. In order to obtain,
* Grasselli Chemical Co., Inc., Empire State Bldg., New York, N. Y.
** Hoechst (marketed by General Dyestuff s Corp., 233 Fifth Avenue, New
York, N. Y.).
Jan., 1933] MAKING FADE-OUTS BY AFTER TREATMENT
73
on each frame, a density which is directly proportional to the dis-
tance from the end of the fade it was necessary to vary the time of
treatment throughout the length of the fade in a manner which is
functionally related to the exponential rate of growth of density with
4.0
2.A
1.6
0.8
IOO ZOO "iOO 4OO 5OO fcOO 1OO
FIG. 5. Dye tinting of motion picture positive film.
time of treatment. A fade-out of this type, the curve of which is
shown at A in Fig. 6, was made by timing the dye treatment accord-
ing to the indications of the curve in Fig. 5, to give a constant rate of
increase in density along the length.
Curve B in Fig. 6 shows the densities produced by leading the film
at a constant rate into the dye solution, a procedure which, as might
be expected, gives very poor results.
40
S.Z.
ZA
l.fo
0.8
FIG. 6.
10, ZA VZ. 40 AB
Dye tinting of motion picture positive film.
•bfe
A, added density proportional to distance of fade-out; B, time of
treatment proportional to distance from end of fade-out; C, timing
by simple crank and connecting rod mechanism.
Curve C in Fig. 6 shows the densities which resulted from times of
treatment which could be given by a simple crank and connecting rod
mechanism. This fade-out was found quite satisfactory.
Of the numerous ways of causing a varying degree of chemical
74 IVES, MUEHLER, AND CRABTREE [J. S. M. P. E.
treatment from one end of the fade to the other, the simplest is to vary
the time of treatment.
DYE APPLICATION
In the case of the application of a dye solution to the film, the
treatment can be carried out according to one of the methods for
which instructions are given below.
(1) With the film strip lying emulsion side up on a flat surface, rub the sur-
face lengthwise with a wad of cotton soaked with the dye solution. Start each
stroke at the end which is to receive the lesser time of treatment. As each frame
in succession receives its full time of treatment, blot it off and guard it from
further contact with the cotton wad. As treatment is discontinued on one frame
after another, the swabbing stroke is thereby shortened more and more. When
the treatment of the whole strip is completed it should be free from spots of liquid
and should not be washed but is ready for use when dried.
(2) If a large number of fades are to be made, it is preferable to treat several
strips at a time by lowering them at a predetermined rate into a tank or tray
containing the dye solution. That end of the strip which is to be bathed for the
shortest time is immersed into the bath last. When the treatment is completed,
draw the strips quickly from the bath, passing them through a squeegee to remove
excess liquid from the surface. The fade is ready for use as soon as it is dry.
The equipment required for this operation depends upon the
method of timing, and may vary from a wooden rod with hooks to which
the various strips are attached, to a completely automatic machine by
which the treatment is timed and the film withdrawn and squeegeed.
The elaboration of the equipment will depend on the quantity of
work to be done, but perfectly satisfactory results can be obtained
with the simplest equipment. Methods of automatically controlling
the time of treatment are discussed below.
TREATMENT OF THE NEGATIVE
The mechanical handling of the negative during treatment is
essentially similar to that of the positive, but certain limitations are
imposed by the nature of the processes. Both reducing solutions
and developers which are used in producing negative fade-outs act
upon the image at a rate which is slower than the rate of diffusion
from the solution into the gelatin. The consequence of this is that
when the film is removed from the bath it contains a considerable
quantity of unused solution which continues to work unless prevented
by prompt action. The operation must be planned, therefore, in
such a way that the treatment of all portions of the fade is com-
pleted simultaneously, and provision must be made for quick re-
Jan., 1933] MAKING FADE-OUTS BY AFTER TREATMENT 75
moval to the next bath or the wash, as the case may be. Usually
the action continues to a slight extent in the subsequent bathing or
washing, but this can be minimized by adequate agitation of the film
in the bath. At any rate, the further action can be made definite and
uniform by proper handling, and allowance can be made for it in the
determination of the time of treatment.
The following procedure assures a satisfactory fade-out when the
times of treatment have been determined properly for the existing
conditions:
(1) The Belitzski, one-bath Farmer, or Iodine-Cyanide reducing
solution should be placed in a tank or tray large enough to accommo-
date the full length of the fade-out. Lead the strip into the bath at a
rate which will give to each frame the time of treatment found neces-
sary in previous trials. Allow the end which is to receive the least
time of treatment to enter the bath last. Keep the liquid moving
during use to assure uniformity of treatment. This is especially
advisable in a shallow tray where natural circulation is very little.
When the treatment is complete, draw the strip out quickly, prefer-
ably through a squeegee, and place it in running water. Agitate
thoroughly during the first minute of the wash to remove the reducer
uniformly.
(2) When the two-bath Farmer reducer is used, the treatment
in the first bath is carried out as described under method No. 1
above. When the film is removed from this solution, it is placed
in the second bath where it should be agitated for 1 minute and then
allowed to remain for about 10 minutes.
(3) The following directions apply for the bleach and redevelop
process: Bathe the whole fade-out in the bleaching solution for a
time somewhat longer than that required to show the pale yellowish
white color through the film support. When bleaching is complete,
remove the film and wash it. (If the permanganate bleach has been
used, the dark brown stain should be removed, before washing, by a
short treatment with a 1 per cent solution of sodium bisulfite.) When
washing is complete, the fade-out is produced by lowering the film end
first into an ordinary developing solution which may be diluted for
convenience in timing.
The end of the fade-out which is to have the greatest density should
enter the developer first. When all portions of the fade have received
the proper times of development as determined in previous trials,
the fade is removed quickly to an acid fixing bath, where it is agitated
76 IVES, MUEHLER, AND CRABTREE [J. S. M. P. E.
for about 1 minute and then allowed to remain for 10 minutes. Fixa-
tion is followed by washing and drying, after which the fade-out is
ready to be spliced to the negative.
It is advisable, before any of the above operations on negatives
are undertaken, to harden the gelatin by treatment for five minutes
in the following hardening solution.
Hardening Solution
(Formula SH-2)
Formalin (40% solution) 5.0 cc.
Sodium carbonate (anhydrous) 5 . 0 grams
Water to 1.0 liter
If the negative has not been properly hardened, reticulation and
frilling of the gelatin are liable to occur in the after processes.
TIMING THE TREATMENT
Although it would appear that the motion of the treated strip of
film should be stepwise so that all portions of a single frame receive
the same treatment, this is not necessary. In a fade of the usual
length, the change is so gradual that no variation in density from
top to bottom of the frame can be detected if the fade is produced by
leading the film into the treating solution by a continuous, instead of
stepwise, motion. This makes possible a wider choice of methods of
timing.
If the handling is to be entirely manual, then the stepwise method
is probably the best choice, because of the difficulty of estimating
the velocity in a continuous motion. It is recommended to adjust
the concentration of the solution so that the process is complete in
about 10 minutes.
If the time of treatment is to vary directly as the length of film
traversed, the film can be led into the bath either one frame at a
time at equal time intervals, or continuously by the use of any one
of the common mechanical arrangements for producing motion at a
constant rate. The use of mechanical timing means is very desir-
able, even though a large part of the process is to be carried on
manually.
If the time of treatment is not required to increase directly as the
length of film, then a more complicated timing means must be
chosen. As shown in Fig. 5, for the dye treatment the relationship
between time of treatment and length traversed is exponential,
a relationship which is not attained precisely in a simple mechanical
Jan., 1933] MAKING FADE-OUTS BY AFTER TREATMENT
77
device. If the motion is controlled by the use of a cam of special
shape the apparatus is somewhat expensive and usually awkward
and difficult to alter for varying the treatment.
A device described in a previous communication2 may be used
for the purpose because it can be adapted very easily to control the
motion in any manner desired. This device is illustrated schemati-
cally in Fig. 7 with some of the other equipment which might be used
for handling the film. The timing element proper consists of a tape
moved at a constant rate under a set of small levers. Perforations
FIG. 7.
Schematic drawing of machine for making fades with
tape for program timing.
made in the tape at the necessary points move the levers, making
electrical contacts by which the film advancement ratchet can be
moved, motors started, stopped, reversed, etc.
There are other devices commercially available for timing a pre-
determined sequence of events, such as the blowing of time whistles,
ringing bells, etc., which might be adapted to this purpose. As men-
tioned above, there is always the possibility that an approximation
of the motion required which is much more readily attained will be
equally satisfactory in practice.
78 IVES, MUEHLER, AND CRABTREE
In the construction of apparatus for the treatments described in
this paper it is necessary to take into account the corrosive nature
of the solutions when deciding upon the material to be used in con-
tact with the bath or the wet film.3
REFERENCES
1 CRABTREE, J. I., AND MUEHLEP, L. E.: "Reducing and Intensifying Solu-
tions for Motion Picture Film," /. Soc. Mot. Pict. Eng., XVII (Dec., 1931),
No. 6, p. 1001.
2 JONES, L. A.: "A New Non-Intermittent Sensitometer," /. Frank. Inst.,
189 (1920), No. 3, p. 303.
3 CRABTREE, J. I., MATTHEWS, G. E., AND Ross, J. F.: "Materials for the
Construction of Motion Picture Processing Apparatus," /. Soc. Mot. Pict. Eng.t
XVI (March, 1931), No. 3, p. 330.
PRACTICAL PROBLEMS IN THE RECORDING AND
REPRODUCTION OF MUSIC FOR MOTION PICTURES*
DAVID MENDOZA**
Summary. — The paper opens with a few remarks on the relation between the
musician and the engineer, and refers particularly to certain inadequacies in the
recording and reproduction of music. The improper acoustical construction of sets
and the inappropriate placing of artists and accompanists are alluded to. The
difficulty of. satisfactorily recording background music is briefly discussed, and a
suggestion is made for overcoming the masking of dialog by background music.
Further remarks are made on the size of sets and various points of technic in recording
and duping.
In discussing the practical problems that confront us in the every-
day experiences on the stages of the studio, let us first disregard en-
tirely the attitude of the industry as a whole — disheartening, to say
the least — toward all endeavors of pioneering into new realms of
imagination and fantasy. I believe that you will agree that unless
startling improvements are made in the recording and reproducing
of sound pictures, even beyond what has been done up to now,
the industry may see a further divorcement between the theater and
the audience than it has already seen.
The musician feels a common bond with the engineer, in respect
to the reproduction of sound, first, because as an artist he depends
so much upon the indulgence of the engineer and, second, because
he is keenly aware of the well-nigh overwhelming technical problems.
I have found the great majority of "mixers" I have worked with to
be most genial and sympathetic; and have sometimes been amazed
at the appreciation shown by these men, not only of sound as spoken
of in decibels, but as regards a fine feeling for music in all its com-
ponents of inspirational value — the balance of orchestration and the
most illusive emotional factors that comprise an artistic performance.
Many present-day troubles result from two factors: (1) a lack of
understanding of the other fellow's problem, and (2) the yet un-
* Presented at a meeting of the New York Section, Oct. 19, 1932.
** Warner Bros. Pictures, Inc., Brooklyn, N. Y
79
80 D. MENDOZA [J. s. M. P. E.
conscious and unexpressed opinions of our audiences at large as to
their reactions to "sound."
I feel that our stages are sorely lacking as to physical proportions
and proper material for the effective recording of music. The stack-
ing of deadening and in many instances reflective sets is most harm-
ful. Our orchestras are shunted into all manner of positions and
locations so as to be out of the way, as it were, of camera lines, and
to be "conveniently" placed. Soloists are usually placed at absurd
distances from the accompanists. Under such conditions, balancing
for the mixer becomes merely a catch-as-catch-can affair. Even on
the coast, with the stupendous stages found on all the lots, the sets
are generally built with a thought only for the cameras.
Another factor that results from a lack of cooperation and under-
standing between departments refers to the matter of orchestration.
The mixer generally hears the first performance of the musical com-
positions in his monitor room, and is not generally aware of some
of the niceties of the orchestration, which should be determined by
the playback.
A few weeks ago we had occasion to place the orchestra on a plat-
form about four feet high, which happened to be built for use as a
bridge in a scene to be shot the next day. By placing the orchestra
on this platform, with its good air space beneath and all the "life"
resulting from the platform, we were afforded one of the most satis-
factory recordings obtained in a long time. This is a point upon
which I put a great deal of stress, for orchestras are expensive and
unless we obtain satisfactory results the efforts and expenditure
involved will have been greatly vitiated.
Now we come to one of the most deplorable facts in connection
with music in motion pictures, namely, "background" music. Of
course, where a picture is silent as far as dialog is concerned, the
music has a pretty good chance to come through satisfactorily, but
when the characters on the screen speak, the music is wholly ineffec-
tive and in any case unsatisfactory. If we were to have an orchestra
in the theater to supply mood and background music for pictures,
the music should emanate from a source entirely different from that
from which the dialog would come. It would be easy to "balance"
the music and dialog, and lose none of the effectiveness of either one
or the other. Would it not be possible to develop a double sound
track, one on each side of the film, and place the projecting horns at
different places in the proscenium of the theater? One track could
Jan., 1933] RECORDING AND REPRODUCTION OF MUSIC 81
carry the music and the other the dialog; the two tracks could be
reproduced on different systems and each could be operated inde-
pendently of the other and reproduced from different points of the
proscenium. This thought may be very impracticable, but as I should
like very much to see something done in this connection, as I feel sure
that the proper musical accompaniment of pictures would greatly
assist in improving the reaction of the audience. I believe that you
will all agree with me that up to the present a really effective back-
ground musical score has not been accomplished.
Also, when a dramatic scene is on the screen and silence prevails
for a few minutes, the issuance of music from the same source whence
comes the dialog seems unnatural. The producers always try to
create an apologia for the music, and either place a radio or a phono-
graph in the scene. The audiences are becoming aware of this
clumsy form of excuse, and are making many humorous comments
about it.
I mentioned before my sentiments regarding the size of our stages.
In the case of close-up recordings of solo instruments, they do not
apply ; but when an orchestra of symphonic proportions is employed
we have found it well-nigh impossible to allow the men to play in full
tone fortissimo, as they would in a concert hall. On the radio we
hear reproductions of symphony orchestras with a great deal of
satisfaction as regards results. Why can we not achieve as good
results on our screen? The only remedy that I can think of is to
utilize recording space so that it permits placing the microphones
at a distance that would allow a natural performance and yet provide
good acoustical results when reproduced. The new developments
recently made in extending the range of reproduced frequencies
could then be fully appreciated.
You have no idea of how great is the difference in the feelings of
musicians when they are allowed to play on a stage that is "alive"
and spacious. Everything seems to be pleasant and simple. The
effect is purely psychological, but it is one of the main factors in our
particular work. The conditions of recording have a tremendous
effect upon the performer. So far, men like Respighi and Ravel have
not been enticed into the motion picture field, and I think that this
is mainly because the conditions existing in recording studios are in
no way as conducive as they should be to a high standard of artistic
achievement.
I remember a story that was told to me about Fritz Kreisler. The
82 D. MENDOZA [j. s. M. p. E.
occasion was a recording date for the Victor Company. Kreisler
took out his violin, stepped before the horn (this was in the "good"
old recording days), and noticed that he was standing on a rug.
He asked the reason for the rug and was informed that it was neces-
sary for acoustical reasons. Thereupon Mr. Kreisler expressed
himself as being unable to play unless he stood on the bare floor.
This story may sound far-fetched and may be foolish as far as net
results are concerned, but as the performer was Mr. Kreisler and
none else, the rug was removed.
Now imagine our trying to perform on crowded stages filled with
all sorts of deadening materials, such as flats, that set up all kinds of
reverberations, and situated so that we have no idea of what the net
balance will be. Yet we struggle on in the hope that some day our
work will be facilitated to a point that will spur our enthusiasm and
imagination.
I do not believe that any method of equalization for duping
purposes is advisable, as I have found that if the original sound track
does not possess all the qualities desired, any attempt to equalize
for the purpose of building up highs or lows generally introduces
some kind of distortion.
I am aware that there are various new improvements being utilized
and experimented on that I understand give results far superior to
what we are producing at present. I sincerely hope that the producers
will be made to realize the advisability of adopting these improve-
ments. The engineers must sell these ideas to these producers,
especially in the matter of theater equipment; for, as is well known,
many of our efforts are vitiated in the net results heard in the neigh-
borhood theaters and, in many cases, I am sorry to say, in the so-called
de luxe motion picture houses.
Of course, few theaters have been built particularly for exhibiting
sound pictures. We hear our product in our small projection rooms,
and are very often enthusiastic over the results. Later we hear it
in one of the Broadway theaters, and the difference is unbelievably
disappointing. The music sounds thin, without the body of sound
that I know was contained in the original recording. High tones are
lost, low tones are lost — "fuzz," "edge," sprocket hole modulation
are produced. The problems in this connection are too numerous
to relate and I am in absolute sympathy with the engineers' efforts.
But when I hear my oboe, clarinet, violin, or trumpet sound like a
Chinese cat, I resent it ! I must resent it ! Poor balance can be
Jan., 1933] RECORDING AND REPRODUCTION OF MUSIC 83
corrected even in mixing, poor performance in rehearsal — and
"fuzz" and "edge" must be eliminated.
A word for duping. This is one of the phases of our business that
I think is still in its most elementary state. An evil in itself and
unavoidable from a practical and economic point of view — but the
relation between the dynamics of music back of dialog plus effects is a
matter of showmanship in its most elementary phase. The dupers
and mixers are endeavoring to be showmen in this sense, and in many
instances they are. The mere audibility of any sound, either music
or effect, is not enough. That the importance of the sound lies in
the frame of the drama or the comedy is the factor to bear in mind.
A moment of drama must be recognized as such, and soft and subtle
treatment is necessary.
Now I do not believe that all these shortcomings are due to in-
adequate equipment. I attribute a great deal of it to faulty and
inadequate acoustics. From the standpoint of dialog, the motion
picture is well exhibited; but from the standpoint of sound, I am sorry
to reiterate that most of the comments of those who pay attention
to this part of the entertainment are always most disappointing.
In conclusion, I wish to state that complete cooperation and very
close association must exist between the music department and
the recording department. A complete understanding of each
other's problems and the exchange of ideas and an honest criticism
of each other's work must be the rule. Temperament will always
be present, but if honesty exist fundamentally, good results will
follow.
ERRATUM
The following correction should be made in the paper, Standards and Require-
ments of Projection for Visual Education, by Chauncey L. Greene, beginning on
page 424 of the November, 1932, issue of the JOURNAL:
On page 432, sixth line from the bottom, the phrase "this class of screen"
should read "the translucent type of screen."
NEW APPARATUS
At recent meetings of the photographic section of the Technicians Branch of the
Academy of Motion Picture Arts and Sciences, and of the Chicago Section of the
S. M. P. E., several pieces of new equipment were exhibited and discussed. The
description of a few of the devices follows. Illustrations were supplied by Mr. J. G.
Frayne, Chairman of the S. M. P. E. Progress Committee and Mr. C. E. Phillimore
of the S. M. P. E. Chicago Section.
Bell & Howell Rotambulator (Fig. 1). — With this new type of sup-
port, the camera may be moved vertically from a point 2 feet above
the floor to nearly 8 feet. Present models utilize a worm drive for
this movement but future models may be equipped with a hydraulic
Courtesy of Bell &• Howell Co.
FIG. 1. Rotambulator.
hoist. The usual pan and tilt, and horizontal movements are
available. The panoramic movement is effected by hydraulic
means, and is controlled by pedals operated by the cameraman, who
sits on a seat arranged to revolve with the camera. The device is
84
NEW APPARATUS
85
Follow- Focus
Device for
Actuating Finder
'Lupe* Light Bracket
Llftlnc Handle (4)
Courtesy of Paramount Publix Corp.
FIG. 2. Sound blimp.
Courtesy of Paramount Publix Corp.
FIG. 3. Camera crane
86 NEW APPARATUS [J. S. M. p. E.
mounted on a heavy frame equipped with three small wide wheels
having rubber tires. A hand bar is provided for moving the rotambu-
lator and the cinematographer.
Paramount Sound BUmp (Fig. 2) . — The illustration is self-explana-
tory. Note that the camera and tripod may be lifted quickly and
easily by the rolling tripod for moving from one setting to another.
Courtesy of Peko, Inc.
FIG. 4. Projector.
Paramount Camera Crane (Fig. 3). — This crane is so designed that
it may be passed through a 24-inch doorway. It is much more
flexible and lighter in weight than many of the earlier cranes used for
motion picture camera work.
Peko Projector (Figs. 4 and 5). — The frame consists of a white-brass
casting about which the entire mechanism is constructed. The
gear train comprises four spur gears and two metal gears. All
bearings are lubricated from tubes leading to the top of the machine.
The intermittent movement consists of a conventional cam and a
double claw straddling the perforations. A two-blade 90-degree
shutter is employed, the picture being projected at the rate of 20
frames per second. The reflector is made of chromium-plated brass.
Jan., 1933]
NEW APPARATUS
87
The base of the projector houses a transformer or, in the case of
d-c. supply, a resistor. The projectors are designed to be operated
by alternating or direct current. The driving belt is crossed to per-
mit reversing the machine or rewinding the film.
The film passes through the projector without being twisted and
ball bearings are used throughout. The reels will accommodate 400
feet of film.
One model is provided with a rheostatic speed control and a special
switch by means of which a resistor is introduced into the lamp cir-
cuit when the motor is at rest, thereby reducing the illumination and
heat sufficiently to permit showing still pictures. Forced ventilation
is also provided.
Courtesy of Peko, Inc.
FIG. 5. Projector mounted in carrying case; right, for direct projection
through front of case; left, for industrial use with daylight screen.
BOOK REVIEW
Einfuehrung in die Tonphotographie. (Introduction to Sound-Photography.)
JOHN EGGERT AND RICHARD SCHMIDT. S. Hirzel, Leipzig, 1932, 137 pp.
This introduction gives a thorough resume of methods of recording sound
photographically. After briefly describing the elementary physics of sound
recording, it deals with the various electrooptical phenomena and their application
to modern methods of recording sound.
The greater portion of the book is devoted to the fundamental principles of
photographic recording. In some ways very elementary, these chapters furnish
a rather complete analysis of most of the known photographic effects on the
sound record and discuss the influence of these effects on the final results: the
reproduced sound. Following a treatise on sensitometry is a chapter on the
fundamental requirements for recording and reproducing sound without distor-
tion. Both the variable area and the variable density systems of recording are
discussed, as well as the noiseless recording systems.
The latter part of the book presents results obtained with Agfa Film TF3 and
TF4; films especially made and adapted for recording sound, which are exten-
sively used in Europe. A proposal for standardization and citations of German,
English, and American literature conclude the volume.
Many graphical charts and drawings, which can be easily understood with but
little knowledge of mathematics, illustrate the formulas.
This book should be of great value to all those interested in the problems of
recording sound. W. SCHMIDT
88
SOCIETY OF MOTION PICTURE
ENGINEERS
OFFICERS
1932-1933
President
A. N. GOLDSMITH, Radio Corporation of America, New York, N. Y.
Past-President
J. I. CRABTREE, Eastman Kodak Company, Rochester. N. Y.
Vice-Presidents
E. I. SPONABLE, Fox Film Corp., New York. N. Y.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
Secretary
J. H. KURLANDER, Westinghousc Lamp Co., Bloomfield, N. J.
Treasurer
H. T. COWLING, Rochester, N. Y.
Board of Governors
H. T. COWLING, 311 Alexander St., Rochester, N. Y.
J. I. CRABTREE, Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
P. H. EVANS, Warner Bros. Pictures, Inc., 1277 E. 14th St., Brooklyn. N. Y.
R. E. FARNHAM, General Electric Co., Nela Park, Cleveland, Ohio.
O. M. GLUNT, Bell Telephone Laboratories, Inc., New York, N. Y.
A. N. GOLDSMITH, Radio Corporation of America, 570 Lexington Ave., New
York, N. Y.
W. C. HUBBARD, General Electric Vapor Lamp Co., Hoboken, N. J.
R. F. MITCHELL, Bell & Howell Co., 1801 Larchmont Ave., Chicago, 111.
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
E. HUSE, Eastman Kodak Co., 6706 Santa Monica Ave., Hollywood, Calif.
L. C. PORTER, General Electric Co., Nela Park, Cleveland, Ohio.
E. I. SPONABLE, Fox Film Corp., 850 Tenth Ave., New York. N. Y.
SOCIETY ANNOUNCEMENTS
SPRING, 1933, CONVENTION
April 24-28, inclusive; New York, N. Y.
At the meeting of the Board of Governors held on October 5 at New York,
plans for the Spring, 1933, Convention were initiated: the meeting is to be held
at New York, N. Y., and of five days duration — April 24 to 28, inclusive.
Mr. W. C. Kunzmann, chairman of the Convention Committee, assisted by
Mr. H. Griffin, chairman of the Local Arrangements Committee, is proceeding
with arrangements to hold the Convention at the Hotel Pennsylvania, in the
Salon Moderne.
Mr. O. M. Glunt, chairman of the Papers Committee, promises an extremely
interesting schedule of papers; the number of papers to be presented will be
limited to what can be accommodated in the allotted time without haste or crowd-
ing, a feature that will assist considerably in the selection of papers from the point
of view of technical quality, with less emphasis on quantity.
An exhibit of newly developed motion picture equipment will be held, as at
past Conventions, which should prove of considerable interest to every one
interested in motion picture engineering. Manufacturers of equipment are
invited to communicate with the General Office of the Society, 33 W. 42nd St.,
New York, N. Y., for information regarding the regulations of the exhibit and
arrangements for space.
Plans are being made to assist out-of-town visitors to the Convention to pass
an interesting time while in New York, and special film programs and trips of
interest will be arranged for. Full details of the program, including hotel rates
and other pertinent information will be mailed to the members of the Society at a
later date. Members and friends of the Society are urged to make every effort to
attend the Convention.
PACIFIC COAST SECTION
At a meeting of the Section held on December 14 at the Walt Disney Studios
in Hollywood, several descriptions of the technical processes involved in producing
animated cartoons were presented. Chairman E. Huse announces an interesting
series of meetings for the coming season, and all members of the Section are urged
to attend the meetings regularly and contribute to the activities of the Section ;
all meetings will be open to both members and friends.
COMMITTEE ON THE CARE AND DEVELOPMENT OF FILM
Reports of the work of the two sub-committees of the Committee on the Care
and Development of Film, one dealing with exchange practices and the other
with laboratory practices, have practically been completed and will be published
90
SOCIETY ANNOUNCEMENTS 91
in the JOURNAL in the next month or so. This work represents a new activity of
the Society, begun hardly a year ago, in collecting all the important data on
current practices in the handling of film in the exchanges and in the laboratories.
Much yet remains to be done, of course, particularly in the matter of paving the
way toward standardization of technic; the work of this year, however, was
directed more toward determining the nature of present technic and correlating
and reconciling divergent technics.
COMMITTEE ON STANDARDS AND NOMENCLATURE
In the November issue of the JOURNAL the report of the Committee on Standards
and Nomenclature, which was presented before the Society at the Washington
Convention last October and returned to the Committee for further consideration,
was published. Accompanying the report was an invitation to all readers of the
Journal who might be interested in motion picture standardization to submit
in writing to the General Office of the Society, comments on or criticisms of the
report. Action of the Board of Governors of the Society will be taken at their
next meeting, on January 20 at Rochester, N. Y., toward the validation or
rejection of the proposed standards in the light of the comments received. Those
who desire to comment on the report are urged to do so immediately, so that their
communications may be received in time for the consideration of the Board.
SUSTAINING MEMBERS
Bausch & Lomb Optical Co.
Burnett-Timken Laboratories
Eastman Kodak Co.
Electrical Research Products, Inc.
RCA Victor Co., Inc.
HONOR ROLL
OF THE
SOCIETY OF MOTION PICTURE ENGINEERS
By action of the Board of Governors, October 4, 1931, this Honor Roll was estab-
lished for the purpose of perpetuating the names of distinguished pioneers who are
now deceased:
Louis AIME AUGUSTIN LE PRINCE
WILLIAM FRIESE-GREENE
THOMAS ALVA EDISON
GEORGE EASTMAN
JEAN ACME LE ROY
FILM RECORDING EQUIPMENT
Type 3S Com-
plete Record-
ing Equipment.
Single or Double System, Variable
Density or Variable Area, Studio
or Portable.
Write or cable for literature
JENKINS & AD AIR, INC.
3333 Belmont Ave.
Chicago, U. S. A.
Cable Address: JENKADAIR
FOR MICROPHONE MIXER CIRCUITS
The Type 652 Volume Control is a slide-wire type
of attenuator combining compactness and low cost
with excellent electrical and mechanical properties.
It uses a ladder-type network which has a linear at-
tenuation characteristic and nearly constant impedance.
The noise level is extremely low.
Impedance: 50, 200, or 500 ohms.
Infinite attenuation, linear from 0 to 45 decibels.
Price: $12.50.
For complete details, address the General Radio Company, Cambridge, Mass.
AL RADIO Co
PRECISION AND DEPENDABILITY
PAMPHLETS, BOOKLETS, AND CATALOGUES
Manufacturers of motion picture equipment and supplies are requested to send
to the General Office of the Society copies of their descriptive pamphlets, book-
lets, and catalogues as issued. Notices of the issuance of this material will be
published in the JOURNAL, advising the readers that the material may be obtained
free of charge by addressing the manufacturers named. This editorial service
has been established in order to acquaint readers of the JOURNAL with the com-
mercial developments of the motion picture industry as quickly as they occur.
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
Volume XX FEBRUARY, 1933
Number 2
CONTENTS
The Photronic Photographic Exposure Meter.
Page
W. N. GOODWIN, JR. 95
Musical Acoustics of Auditoriums P. CAPORALE 119
A New Western Electric Double Film Portable Sound Record-
ing System C. "R.DATT.v 128
Engineering and Scientific Charts for Lantern
List of Members
Slides 142
151
Book Review
172
Officers
. 173
Committees
174
Society Announcements
177
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
SYLVAN HARRIS, EDITOR
Board of Editors
J. I. CRABTREE, Chairman
L. DE FOREST A. C. HARDY F. F. RENWICK
O. M. GLUNT E. LEHMANN P. E. SABINE
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.
Publication Office, 20th & Northampton Sts., Easton, Pa.
General and Editorial Office, 33 West 42nd St., New York, N. Y.
Copyrighted, 1933, by the Society of Motion Picture Engineers, Inc.
Subscription to non-members, $12.00 per annum; to members, $9.00 per annum,
included in their annual membership dues; single copies, $1.50. A discount
on subscriptions or single copies of 15 per cent is allowed to accredited agencies.
Order from the Society of Motion Picture Engineers, Inc., 20th and Northampton
Sts., Easton, Pa., or 33 W. 42nd St., New York, N. Y.
Papers appearing in this Journal may be reprinted, abstracted, or abridged
provided credit is given to the Journal of the Society of Motion Picture Engineers
and to the author, or authors, of the papers in question.
The Society is not responsible for statements made by authors.
Entered as second class matter January 15, 1930, at the Post Office at Easton,
Pa., under the Act of March 3, 1879.
THE PHOTRONIC PHOTOGRAPHIC EXPOSURE METER*
W. N. GOODWIN, JR.**
Summary. — This paper describes a new photographic exposure meter, which
measures the brightness of the scene to be photographed. It utilizes for its light
measuring element two Weston photronic photoelectric cells connected in parallel
to, and mounted in the same case with, a permanent magnet movable coil indicating
instrument calibrated in units of brightness: candles per sq. ft. The cells are of
the direct action dry disk type, which transform light energy directly into electrical
energy, requiring no battery, and having an unlimited life. They are mounted in
tubular depressions to limit the area of the scene covered.
A simple mechanical dial calculator attached to the meter case translates light
values into exposure values by a single setting of a dial, after having set the calculator
once for all for the speed of the film being used. The calculator has the novel feature
of providing means for fitting the brightness range of a scene as determined by its
darkest and brightest objects, to the correct film range indicated on the dial as lying
between the darkest and brightest objects which the film will correctly expose, for the
indicated shutter speed and aperture.
There is probably no problem encountered by the photographer
that is more troublesome than that of determining the correct
exposure. Even after long experience one is usually in doubt in
estimating exposure, especially at times other than mid-day and for
any but the most usual subjects. For such conditions, estimates
made visually are little more than guesswork. The very fact that
the human eye is capable of adapting itself automatically to such
extreme variations in light intensities makes it exceedingly in-
accurate as a means for judging the relatively narrow range of light
values for correct exposure, especially under unusual conditions.
Light tables, which give average values arranged according to
months, time of day, and character of lighting, are in extensive use;
but they fail during early morning and late afternoon, and under
unusual and abnormal conditions. While it is a fact that modern
films have a wide latitude, or film range, as it is termed in this paper,
the actual scene exposure range, or choice of exposure, is very narrow,
* Received by the editor, September 28, 1932.
** Weston Electrical Instrument Corp., Newark, N. J.
95
96
W. N. GOODWIN, JR.
[J. S. M. P. E.
as will be referred to later in detail. It is for this reason that among
the many exposures one makes, only a few are really satisfactory,
as every photographer knows.
To obtain correct exposure, therefore, it is necessary to be able
to measure the actual light intensities at the time the exposure is
to be made.
FIG. 1. Front view of meter.
The exposure meter described in this paper utilized for its light
measuring element two Weston photronic photoelectric cells. These
are of the direct action, dry disk type, in which the light energy is
transformed directly into electrical energy, requiring no battery
for their operation. As they are purely electronic in their action,
their lives are unlimited as far as is known.
FIG. 2. Rear view of meter.
The cells are directly connected to an electrical measuring instru-
ment mounted in a common case as illustrated in Fig. 1 showing a
front view, and in Fig. 2 showing the cell construction in the rear.
A mechanical calculator is provided for translating the instrument
indications into exposure values.
Feb., 1933]
PHOTRONIC EXPOSURE METER
97
The instrument is calibrated to read in terms of the brightness
of the subject to be photographed, as this is the quantity that de-
termines the intensity of the illumination falling upon the plate to
be exposed.
Before discussing the exposure meter in detail it is desirable to
consider briefly some of the fundamental relations of illumination
and exposure. To show the relation between the brightness of the
subject and the resulting illumination on the plate or film in a camera,
refer to Fig. 3.
Let A be a portion of the subject to be photographed, which is
either self-luminous or becomes luminous
as a result of reflection of light from the
sun, sky, or other illuminant. Assume
that it has a uniform brightness of B
candles per sq. ft. and that it is situated in
a plane perpendicular to the axis of the
lens, at a distance, Dt from the lens, relative
to which, the distance between lens and
aperture may be neglected. For simplicity
of illustration, assume a single lens and
a diaphragm with a circular opening having
a diameter, d. Then the image of the sur-
face A , properly focused on the plate, will
have an area a at a distance, F, from the
lens, all distances being measured in the
same unit. Each point, pi, of the object
will produce a cone of light rays having
as a base the circular opening of the
diaphragm as shown by the solid lines,
FIG. 3. Light diagram and
which again, reunite in a corresponding illumination in a camera.
point, p2, of the image.
The total luminous intensity of the surface A is the product of
the area by the brightness, or AB candles, and the intensity in the
direction of the lens is AB cos 6 candles. The resulting illumination
at, and in the plane of the diaphragm, is
AB cos4 0
foot-candles in accordance with the well-known laws of light, where
(D/Cos 6) is the distance of the object from the lens, remembering
98 W. N. GOODWIN, JR. [j. s. M. P. E.
that the light enters d at an angle 0 with the normal and assuming
that all distances are measured in feet.
The amount of light, in lumens from the surface A entering the
diaphragm, is the product of the illumination at that point by the
area of the opening, or
AB cos4 6 ird*
D* X 4
Part of this light is absorbed by, or reflected from, the lens, and
only a part is available for the image, which is obtained by multi-
plying the total light by the transmission factor of the lens, T;
or the light available for the image is
AB cos4^ Trd'
- £2 - x "4" x T lumens
Now this light is distributed over the image having an area a so
that the illumination at a is the total light in lumens divided by the
area, or
_ AB COS4!? .. «** _,
E = — = -- X — r- X T foot-candles
4
From well-known optical laws the following proportionality holds,
4. = £?
a ~ F*
Substituting for A /a hi the above equation for E, its equivalent
and rearranging terms, we have
E = x cos4 e foot-candles
which shows that the illumination on the plate available for pro-
ducing an image is proportional to the brightness of the object,
independent of its distance from the lens except for its slight effect
upon the distance F, which will be referred to later, and inversely
proportional to the square of the ratio of the focal length of the
lens to the diameter of the diaphragm opening. It also shows that
the illumination is not uniform over the area of the plate but, under
the assumed conditions, falls off from the center in proportion to the
fourth power of the cosine of the angle of incidence of the light.
Practically all lenses are marked by their manufacturers with
/"/numbers or some function of them, which are the ratios of the
principal focal length of the lens to the diaphragm openings. Call
Feb., 1933] PHOTRONIC EXPOSURE METER 99
this value/, and substitute it for (F/d) in the equation; insert the
numerical constants, and change to meter-candles, which is the
unit usually employed in photographic work, by multiplying by
10.76; we obtain
7?T"
E = 8.45 -«- cos4 0 meter-candles
Assuming an average angle 0 of 16 degrees and a transmission
factor for the lens of 76 per cent, the measured value for a well-
known make of lens, which, however, may vary considerably for
different makes of lenses, we obtain the illumination of the image:
•n
E = 5.4 -^ meter-candles
ELEMENTARY THEORY OP EXPOSURE
When light falls upon a photographic plate or film, the action
upon the sensitized material depends upon the intensity of the
illumination and upon the time the light is allowed to act. Ex-
pressed mathematically, the exposure is e = Et, where t is the time
the illumination E acts upon the film in seconds.
Then substituting the value for E deduced above, we have
R/
e = Et = 5.4-7^ meter-candle seconds
It is thus shown that the brightness of an object is the true criterion
of exposure, and not the intensity or quality of light falling upon
the object, as is frequently used. The equation further shows that
the exposure is inversely proportional to the square of the / number,
as is well known.
For objects at relatively great distances from the lens, the / in
the equation depends upon the principal focal length of the lens,
and for convenience the maker of the camera bases the //numbers
upon this value. These //numbers are sufficiently close to the
actual values for distances within 10 times the focal length of the
lens. The actual //number for any distance can be computed by
the following equation derived from the usual lens equation:
where /i = actual //number, / the marked number, and n the ratio
of the distance from the object to the lens, to the focal length of the
lens.
100
W. N. GOODWIN, JR.
[J. S. M. P. E.
We have considered so far only the illumination available on the
photographic plate and the time it acts, the product of which is the
exposure, and we shall now discuss briefly the action of this exposure
upon the photographic emulsion so as to determine the direct relation
between the brightness of an object to be photographed and the
resulting effect in the final negative.
When light falls upon a sensitized plate or film, a physical change
takes place that is well known, the resulting change depending upon
the intensity and color of the illumination on the plate or film;
upon the time it acts; and upon the sensitivity of the emulsion.
When the plate is subsequently developed, the sensitized silver
salts that were acted upon by light are reduced to metallic silver,
2.0
1.5
TAN
a
V& V* /2p,1 2 4 8 16 32 64 128 256 512
RELATIVE EXPOSURE
FIG. 4. Typical H & D characteristic curve of photo-
graphic plates and films.
and the amount of reduction is a function of the exposure and the
time of development. This effect was made the subject of scien-
tific investigation by Hurter and Driffield. They found that, for a
given development, if values of density be plotted against the loga-
rithms of the exposures, a characteristic curve results, as shown in
the typical curve in Fig. 4, known as the H & D curve. In the
straight portion the relative densities are proportional to the loga-
rithms of the exposures, as is required for correct rendering of light
values. Hurter and Driffield further found that the actual densities
increase with the time of development. The density D is defined
as the logarithm, to the base 10, of the opacity of the film, which
is the ratio of the light incident upon the film to that which passes
through it.
Feb., 1933] PHOTRONIC EXPOSURE METER 101
For purposes of illustration the abscissas are designated in terms
of relative exposure, and are plotted logarithmically, each value
being double that of the preceding one. Hurter and Driffield found
by experiment that the slope of the curve increases with the time
of development and that the straight portion, when extended, swings
around a point p which, for simplicity, is shown as lying in the line
of zero density, but which frequently lies below it. The tangent of
the angle that the straight portion makes with the horizontal is
known as 7 (gamma). The value of 7 is a measure of the contrast
of the film ; that is, it gives the rate of change in density with respect
to changes in the logarithm of the exposure.
The exposure corresponding to the point at which the straight
portion intersects the horizontal axis is known as the inertia, and
its reciprocal is customarily used as a measure of the speed of the
film. On the curve of Fig. 4 the inertia is the exposure corresponding
to the point p; but where p lies below the line, the inertia value
moves along the exposure axis with changes in 7, showing that the
emulsion speed varies with development time.
The curve may be divided into three parts: (1) the lower end,
which deviates from a straight line at the point d, known as the toe.
This is the region of underexposure. (2) The straight portion,
which is the region of correct exposure. (3) The upper portion,
which extends beyond the straight line at the point b known as the
shoulder, is the region of overexposure. These terms do not mean,
however, that the under and overexposure regions are not frequently
useful and often used. Darkest subjects and the brightest high-
lights of any scene may well extend into the lower and upper regions,
respectively.
The curve illustrated is typical of average commercial films. It
will be noted that the range of the film where correct exposure may
be obtained represents an exposure ratio of about 128 to 1. This
ratio varies for different types of film and with the time of develop-
ment, but for the purposes of exposure meter design, this safe average
value for the film range was used.
Any given scene to be photographed consists in general of objects
of differing degrees of brightness and color, and the problem 'in
exposure is to adjust properly the range of light values of the scene
so that it lies within the range of the straight-line portion of the
characteristic curve. For example, if in a given scene the ratio of
the brightness of the brightest object to that of the darkest object
102 W. N. GOODWIN, JR. [j. S. M. P. E.
in which detail is desired is 32, say, then the brightness range will
be only one-fourth the film range, that is, 32 divided by 128; and
the scene range of 32 will be correctly exposed if it is placed any-
where on the 128 to 1 film range. On the other hand, if the bright-
ness range is approximately 128 to 1 then the photographer has no
choice and the exact exposure must be known.
As briefly referred to earlier in the paper, modern films have
great latitude or film range, but it does not follow that they have
an equally great scene exposure range, that is, choice of exposure.
In the example given above for the relatively narrow brightness
range of 32 to 1, if this range is placed at the low end of the film
range, then any exposure less than the correct value will result in
underexposure of the lower tones, but an increase in exposure of
4 to 1 will still give a good negative. If the scene range is set to give
a medium density in the film range, then an error in estimating
exposure exceeding a ratio of 2 to 1 will result in either underexposure
or overexposure. That is, the scene exposure range is only 2. It
has been found by experience that in general even amateurs who
have had long experience can not estimate so closely as this, which
no doubt accounts for so many poor negatives. For wider brightness
ranges, the scene exposure range diminishes and correct estimates
of exposure become increasingly difficult. It is obvious, therefore,
that some means of correlating brightness and film ranges is necessary
for the best work, and it is for this purpose that the present exposure
meter was developed.
THE EXPOSURE METER
The meter consists of two parts: (1) a means, previously de-
scribed, of measuring the average brightness of an entire scene or
the brightness of any object in it, and (2) a simple calculator for
translating the measured brightness into the proper diaphragm
apertures (stops) and shutter speeds for correct exposure.
The photronic photoelectric cells are arranged in tubular depres-
sions in the back of the case, as shown in Fig. 2. Extended tubes
might have been used to limit the extent of the scene covered, but
following a suggestion by D. R. White of the Du Pont Film Mfg.
Corp., thin metal partitions were used. These were designed to
limit the view to a cone having an angle of about 60 degrees.
The cells are connected in parallel to an electrical indicating in-
strument of the permanent magnet movable coil type. Advantage
Feb., 1933]
PHOTRONIC EXPOSURE METER
103
is taken of a very interesting property of the photronic photoelectric
cell. Its resistance increases greatly as the incident illumination
is decreased, so that a sensitive instrument having a very high-
resistance movable coil may be used. As the cell resistance is so
high near zero light intensity, the instrument resistance has little
effect upon the current output for low intensities. As a result the
scale is expanded at the low end where sensitivity is required. This
360
340
320
300
280
13260
§240
<220
0
160
140
120
100
80
60
40
20
i — i — i — i i i i i i r~
WESTON PHOTRONIC PHOTOELECTRIC CELL
EFFECT OF EXTERNAL RESISTANCE ON
CURRENT OUTPUT
UN6STEN FILAMENT SOURCE AT 3000 K
n
ExKes.-
.3 ohms
100-1
500
20 40 60 80 100 120 140 160 180 200 220 240
ILLUMINATION IN FOOT-CANDLES
FIG. 5. Curves of current vs. illumination for photronic
photoelectric cell.
effect is illustrated in the current response curves of the cell for
various external resistances shown in Fig. 5. It will be noted that
the current for low intensities is nearly independent of the resistance.
THEORY OF THE BRIGHTNESS METER
Let M in Fig. 6 be a surface of any shape, plane or curved, and
at any angle relative to the photoelectric cell P, limited only by the
104
W. N. GOODWIN, JR.
[J. S. M. P. E.
requirements that it must be a perfect diffuser, or practically so,
of a uniform brightness of B candles per sq. ft., and that it is of
sufficient size and so located that no light enters the photoelectric
cell other than that emitted by the surface. The cell is located at
the bottom of a tube or its equivalent so as to limit the light incident
upon it to a comparatively small solid angle represented by the
dotted lines.
Let A be the total area covered by the cell and dA an element of
that area. As dA is very small it can be considered as a plane, and
FIG. 6.
Light diagram used in theory of surface bright-
ness and photronic exposure meter.
since its brightness is B candles per sq. ft. its light intensity is BdA
candles normal to the surface. The illumination at the cell, normal
to the direction of the light produced by the area dA, is then
B cos <p dA
dE ^-
where <p is the angle that the light beam makes with the normal to
the surface, and r is the distance from dA to the cell. This radiant
flux entering the cell produces an elementary current di = idE,
where i = the current produced by unit illumination, say, for 1 foot-
Feb., 1933]
PHOTRONIC EXPOSURE METER
105
candle normal to the direction of the light, and is a function of the
angle of incidence, 6; of the cell arrangement; and of its sensitivity.
Then
,. .,„ Bi cos <p dA
di = idE = - p- -
But cos (pdA/r2 is the solid angle subtended by the projection of
dA in the direction of r, or di = Bi dai, where du is this elementary
solid angle. Then the current for the total area A is
/ = fsi
do>
This shows that the effect upon the cell is independent of the
FIG. 7. Hemispherical distribution diagram
used in theory of surface brightness.
shape or location of the surface, provided the limitations referred
to above are adhered to.
The integral J* Bi du can not be evaluated mathematically for
the reason that i can not be expressed in general as a function of
a? or of 6. However, it can be changed into a form that can be
evaluated from data readily obtained experimentally, as follows:
Referring to Fig. 7, P is the cell that is assumed circular, situated
at the center of a hemisphere of unit radius. Consider an elementary
circular strip dd that has a radius sin 6, a circumference of 2?r sin 0
and an area of 2ir sin 6 dd, since the radius is unity. This is the
elementary solid angle du also, since the radius is unity.
Substituting this value for du> in equation / = J* Bi da> we obtain
/V/2
Jo
7 = 2irB
Bi sin 6 dd or
»/j
* sin 9 dd
106
W. N. GOODWIN, JR.
[J. S. M. P. E.
This states mathematically that the current / generated by the
cell equals 2irB tunes the area of the curve having the equation
i sin 6, between 0 and 90 degrees, which can be determined experi-
mentally. It is necessary only to place the cell at a known distance
from a luminous source of known candle-power, arrangements being
made to change the angle 6 from 0 to 90 degrees. The current per
foot-candle is then measured for as many values of 0 as will give a
curve whose area is to be computed. Such a curve is shown in Fig. 8.
This curve shows that most of the area is included within an angle
10
20 30 40 50 60
ANGLE OF INCIDENCE, DEGREES
70
90
FIG. 8. Current generated in cell of brightness meter by illumi-
nation of one foot-candle normal to direction of light, at angle of
incidence 8, multiplied by sin 6.
of 30 degrees from normal incidence and, therefore, for practical
purposes, only light coming within this angle is effective in pro-
ducing an indication. In deducing this equation it is assumed that
the cell construction is symmetrical about its axis, which is not
strictly true on account of the square-shaped openings.
The area of this curve is a constant, depending solely upon the
cell sensitivity and the construction of the parts in which it is mounted
and, of course, need be determined but once. Call this constant
K, and we have I = 2-jrBK or B = I/2irK candles per sq. ft.
The electrical instrument, therefore, can be calibrated to indicate
Feb., 1933] PHOTRONIC EXPOSURE METER 107
brightness directly. This method is not the simplest one to use
but was described to illustrate the principle of the instrument.
Another method of calibrating or checking the instrument in
brightness units, much simpler than that just described, is to direct
the cells toward a diffusing surface large enough so that no other
light enters the cell, of known reflection factor R, uniformly illumi-
nated by a luminous source of known candle-power to a measured
value R foot-candles. The well-known relation then gives the
brightness B = ER/ir candles per sq. ft.
The ordinary scene, of course, is in general not of uniform bright-
ness and when the meter, calibrated for uniform brightness, is
directed toward such a scene, it indicates the average value. Ex-
perience has shown that this value when properly used gives in most
cases a relatively high accuracy in determining photographic exposure,
as will be shown later.
The instrument usually has two ranges, 0 to 1300 and 0 to 130
candles per sq. ft. The high range is obtained by shunting the
low range through a contact key, which is normally closed. When
the key is depressed, the shunt is open-circuited and the instrument
indicates on the low range.
THE CALCULATOR
The calculator, shown in Fig. 9, consists of three dials, L, T, and
E. Dial L is fixed and gives the light values in candles per sq. ft.,
with numbers from 1 to 1300 corresponding to those on the instru-
ment scale. This dial also contains numbers corresponding to
plate speeds.
Dial T is the time dial, graduated in shutter speeds from 1/soo
second to 64 seconds. It is movable, but requires adjustment only
when the kind of film used is changed, as, for example, when changing
from regular to super-panchromatic. This dial is held in position
by a pin, and to change its position it has purposely been made
necessary to lift the dial to the next pin position in order to prevent
accidental displacement without the knowledge of the user. It can
be set so that its index points to the speed of the film being used.
Dial E is the working dial, and requires but one setting to determine
an exposure. This dial contains the scene positions and the stop
values, graduated from //1. 5 to //32.
The values on the dials and their relative locations depend upon
the equation, developed above, for exposure; and upon film char-
108 W. N. GOODWIN, JR. [j. s. M. p. E.
acteristics determined experimentally. They are based on the
speed of high-speed orthochromatic film, examples of which are
Verichrome and Plenachrome, which is arbitrarily given the number
16. They increase logarithmically, each division having a value,
the effect of which upon exposure is approximately equal to \/2
times that of the preceding one. That is, the effects are doubled
for every second division. In the case of the //scale, it is also the
effect upon the exposure that doubles every second division; there-
fore, since exposure varies with the square of the //number these
numbers double every fourth division. Any of the scales may be
extended in either direction indefinitely by counting divisions, re-
membering that the effective values double every second division.
FIG. 9. Mechanical calculator.
It would have been desirable to measure brightness in metric
units as is customary in photographic work, but these units gave
unwieldly figures for values of brightness occurring in nature.
Candles per sq. ft., however, gave values that were satisfactory.
A brightness of one candle per sq. ft., for example, will produce a
just visible density on a sensitive emulsion in a camera having an
ordinary fast lens at the lowest shutter speed for instantaneous
exposure.
The calculator is so designed that it indicates the limits of the
film range for correct exposure, which lies between the positions
marked Darkest Object and Brightest Object, and provides means for
properly adjusting the brightness range of the scene to the film
range so as to produce the best exposure. In this manner it takes
care of the entire range of light values in the subject.
Feb., 1933] PHOTRONIC EXPOSURE METER 109
The position designated Darkest Object Correctly Exposed* is so
located that, when set to any light value, an object having that
brightness, when used with the indicated values of stop and shutter
speed, will result in an exposure on the plate or film corresponding
to the lower end of the straight portion of the characteristic curve.
The position designated Brightest Object Correctly Exposed in a
similar manner, when set to any light value, indicates values of stop
and shutter speed which, for objects having that light value, will
result in an exposure corresponding to the upper end of the straight
portion of the characteristic curve.
This may be visualized by assuming a strip of the photographic
film or plate placed around the circumference of the light value
dial L, and that the dial E is set to any position relative to dial L.
Then, using the shutter speed and aperture indicated for this posi-
tion, if the film could be exposed at each light value division on dial
L by the light from an object of corresponding brightness, there will
result, after development, a variation in density along the strip.
This increases in equal increments for the light values lying between
the Darkest Object and Brightest Object arrows on dial E, from the
minimum correct density at the Darkest Object arrow to the maxi-
mum correct density at the Brightest Object arrow. For light values
below and above these arrows the density does not change pro-
portionally, and those portions of the film are in the underexposed
and overexposed regions, respectively.
This is true for any position of the dial E when the indicated
shutter speed and aperture for that position are used, and thus the
calculator provides a means of placing the brightness range of a
scene on the correct density range of the emulsion.
BRIGHTNESS RANGE METHOD
In any scene to be photographed, therefore, if one can measure
the brightness of the darkest and brightest objects in which detail
is desired, it is necessary only to set the dial E so as to include these
extremes of scene light values on dial L anywhere between the
Darkest Object and Brightest Object arrows on dial E, and a correct
* Since this paper was written the designations on the calculator dial have
been changed with the idea of making their meaning more clear, as follows:
Brightest Object Correctly Exposed is changed to Brighter Objects Will Be Over-
exposed and Darkest Object Correctly Exposed to Darker Objects Will Be Under-
exposed.
110 W. N. GOODWIN, JR. [j. s. M. p. E.
exposure will result, if the indicated shutter speed and aperture
are used.
If the dial E is set so that the brightness range comes at the lower
end of the film range, then the average density of the film will be
low, and it will be a quick-printing film; if the brightness range is
set midway in the film range, the film will have a medium density;
and if set at the upper part, the film will have the maximum safe
density and will be a slow-printing film. This method affords the
photographer a means of obtaining exposures of any desired density
within reasonable limits.
DARKEST OBJECT METHOD
It is usually quite sufficient in ordinary scenes to measure the
brightness of the darkest object or darkest shadow in which detail
is desired if these can be approached sufficiently close to be measured,
and then set the Darkest Object arrow to the value of the mea-
sured light value and adjust the camera to the indicated shutter
speeds and aperture.
All objects in the scene will then be correctly exposed up to the
brightest objects, provided the brightness of these objects does not
exceed the limit of the film range, which is about 128 times that of
the measured value of the darkest object and indicated by the value
opposite the Brightest Object position on the dial. For example,
suppose that a building is to be photographed and that it is desired
to obtain details in the shadows, which are found by measurement to
have a brightness of, say, 4 candles per sq. ft. Then setting the
Darkest Object position to 4, it will be observed by referring to the
dial E that all objects in the scene having a brightness up to 500
candles per sq. ft., if any are present, will be correctly exposed if the
indicated exposure is given. This upper value is greater than is
usually found in such a scene. When the brightness of the brightest
object is considerably less than that indicated as the Brightest Object
Correctly Exposed, then, as referred to above, the general density
level of the film may safely be increased, if desired, by increasing
the exposure, provided the brightness of the brightest object in
the scene does not exceed the value indicated on dial L as the Brightest
Object Correctly Exposed.
SUBSTITUTION METHOD
When the brightness of a dark colored object in the shade is very
low so that it can not be measured with accuracy on the instrument,
Feb., 1933] PHOTRONIC EXPOSURE METER 111
or possibly not at all, its approximate value may often be determined
by the following substitution method:
The object, as, for example, the trunk of a tree in the woods or
the side of a dark colored building, usually has one side or a part
well illuminated; and if not, similar objects in the vicinity may have.
Measure the brightness of the lighter side, then place a white or a
light colored surface, such as a sheet of paper of ordinary letter
size, on the same part of the surface where the first measurement was
made, and measure its brightness. The ratio of the two readings
gives the ratio of the reflection coefficients of the paper and the
object. Then place the paper on the dark side, the brightness of
which is desired, and again measure its brightness. The brightness
of the dark object can then be computed by dividing the paper
brightness just measured by the ratio found in the first measurement.
For example, assume a scene under trees, the darkest object of
which is the trunk of a tree, the details of which are to be rendered
in the photograph. As is often the case, spots of sunlight illuminate
parts of the tree trunk, or that of some similar tree ; measurement of
a bright spot gives, say, 50 candles per sq. ft. Placing a sheet of
white paper on the same spot gives a brightness of, say, 600. The
ratio of the reflection coefficients is then 12. Now, placing the sheet
of paper on the dark side, and finding it to measure, say, 3 candles
per sq. ft., it follows that the brightness of the dark side is 8 divided
by 12 or J/4 candle per sq. ft. The position on the calculator dial L
for this value is at the fourth division below 1.
BRIGHTEST OBJECT METHOD
In very dark subjects, such as interiors, dark ravines, etc., where
the darkest objects are so much less bright than 1 candle per sq. ft.
that they can not be measured by the instrument, and where the
substitution method is not convenient, the brightest object in the
scene in which detail is desired may be measured, and the arrow on
dial E designated Brightest Object set to the measured light value.
Then, setting the camera to the indicated stop and shutter speed,
all darker objects in the scene down to Ymth the brightness of the
object measured will be correctly exposed. In using this method,
accidental highlights, such as windows looking outdoors, or sun
spots in ravines, etc., should not be measured as the brightest object.
This method is limited by the fact that the meter is not sensitive
to light values less than about 1 candle per sq. ft., which is the bright-
112 W..N. GOODWIN, JR. [j. s. M. P. E.
ness of a white surface placed about 4.5 feet from a 60- watt lamp.
This limitation is the result of the otherwise very desirable feature
of a small and compact size. However, in such scenes, especially
interiors, the photographer usually increases the illumination for
better effects and the meter can be used. If no object is bright
enough to give an indication, then frequently a sheet of white paper
may be properly placed and used as a test object.
AVERAGE BRIGHTNESS METHOD
There are many situations in which it is not convenient, if not
impossible, to approach sufficiently close to the darkest or brightest
objects to measure their brightness. In such cases it is necessary
to measure the average brightness of the entire scene by directing
the meter toward it. In any case, however, the problem is still
to determine the brightness range of the scene, and to do this it
is necessary to know the ratio of the average value to that of the
darkest and brightest objects in which detail is desired. This,
however, is the problem for the instrument designer, and is auto-
matically taken care of in the calculator. As the result of experience
it has been found that, if all scenes are divided into three classes,
this brightness ratio can be predetermined for each class with suffi-
cient accuracy for most practical purposes. The three classes of
scenes have been designated A — Distant or Weak Contrast, B — Normal,
and C — Dark and Strong Contrast. Scenes A consist usually of those
having a high brightness level and weak contrast, such as clouds
and distant scenes, and, as' can be computed by counting the di-
visions on dial L indicated by dial E, Fig. 9, the ratio of the average
brightness to the darkest object that could be correctly exposed,
if it were present, is 6 to 1.
Scenes C consist of dark streets, ravines, etc., where the general
level of brightness is low, even at midday, with no bright highlights ;
and also of scenes where the contrast is extreme, in which the ratio
of the brightest to the darkest objects approaches the limits of the
safe film range, 128 to 1, where it is desired to obtain detail in the
dark objects even at the expense of overexposing the highlights.
For such scenes the calculator provides a ratio of average value
to darkest object of 48 to 1.
Scenes B represent those not included in A and C, and are the
usual normal subjects. In these the highlights and shadows are
not extreme, and are about evenly divided. The calculator provides
Feb., 1933] PHOTRONIC EXPOSURE METER 113
for a ratio of average brightness to that of the darkest object of
16 to 1, and a ratio of brightest object to average of 8 to 1.
It may be of interest to know the approximate values of brightness
of some of the usual objects in nature. These are given in Table I.
TABLE I
Approximate Brightness of Familiar Objects
Objects — near Midday Candles per Sq. Ft.
Clear Blue Sky — Summer 250- 350
Blue Sky with White Clouds 400- 800
Sky with Light Haze 1000
Light Buildings in Sun 150-1000
Light Buildings in Shade 20- 40
Green Foliage in Sun 100
Cement Sidewalk in Sun 200- 600
Cement Sidewalk in Shade 30
Average Distant Scenes 300- 700
Average Normal Scenes 100- 250
Average Dark Scenes Up to 80
Under Trees, Dense Foliage Up to 10
EFFECT OF COLOR AND LIGHT SOURCE
As is well known, the photographic sensitive material is not
equally sensitive to all colors even in panchromatic films, and further,
the various sources of illumination differ greatly in the relative
amounts of the different colors that they radiate. For example,
tungsten illumination has relatively little blue and green but is
rich in yellow and red rays, whereas sunlight has relatively much
more blue and green.
In Fig. 10, curves are given showing the spectral response of the
photronic photoelectric cell; the spectral sensitivity of the normal
human eye, known as the visibility curve; and the spectral dis-
tribution of energy radiated from various sources, all computed to
have the same visual intensity by the following method:
Relative spectral energy curves for the corresponding color tem-
peratures were taken from Critical Tables at arbitrary energy levels
and the luminosity curves obtained for each by multiplying the
ordinates of each curve by those of the visibility curve at corre-
sponding wavelengths. These curves were then integrated by de-
termining the area included under each, to obtain the luminosity
from each source, which follows from the equation
f
"Jo
114
W. N. GOODWIN, JR.
[J. S. M. P. E.
Where L = luminosity
jEx = relative radiant flux at wavelength X
and Fx = visibility function at X
In general, these areas will not be equal, but for the same visual
intensity they must be equal; therefore, one of the spectral energy
curves was assumed as the standard and all the ordinates of each of
the others were changed in the ratio of the area of the luminosity
curve of the standard to the area of the corresponding luminosity
curve of each of the others.
Spectral energy curves drawn with these computed ordinates
180
160
140
U
9120
£100
°
60
P 40
20
K EAI J Ni )ON
TRAL ENERGY DISTRIBUTION OF RADIATION FROM,
^SOURCES HAVING THE SAME VISUAL INTENSITY,
AND THE SPECTRAL RESPONSE OF THE PHOTRONIC
TOELECTRIC CELL . (RELATIVE
\
N.
EGTRIC CELL
CURV
300
400
500
WAVE LENGTH
600
700
800
FIG. 10. Photronic photoelectric cell spectral response, and spectral energy
distribution of various illuminants of equal visual intensity.
as given in Fig. 10, therefore, all produce the same luminous intensity.
The current generated in the photronic photoelectric cell by the
special distribution of radiation corresponding to these curves is
f
Jo
Where / = the current generated
jEx = radiant flux per unit X at X
Px = current generated per unit radiant flux at X
Feb., 1933]
PHOTRONIC EXPOSURE METER
115
To determine the current, therefore, it is necessary only to form
the current distribution curves by multiplying the ordinates of the
photronic photoelectric cell response curve by those of the spectral
energy curves at corresponding wavelengths, and to integrate them.
This has been done, and it is interesting to find that the three sources,
tungsten at 3000°K., mean noon sun, and equivalent daylight at
5400°K., all produce the same current output from the cell for the
same visual intensity, within a small percentage, which in the above
computation was 21/z per cent. This has been corroborated by actual
180
160
140
j
5120
SPECTRAL ENERGY DISTRIBUTION OF RADIATION
FROM VARIOUS SOURCES HAVING THE SAME VISUAL
INTENSITY AFTER PASSING THROUGH AN AVERAGE
AND
SPECTRAL SENSITIVITY OF HIGH SPEED
PANCHROMATIC FILM FOR EQUAL ENERGY.
FIG. 11. Sensitivity of high-speed panchromatic film and spectral energy
distribution of various illuminants of equal visual intensity, after passing
through a lens.
tests for sunlight and tungsten at 3000°K. to within the limits of
experimental error.
Fig. 11 shows the spectral distribution of energy from the various
sources reaching the photographic film after passing through an
average lens. These curves are obtained by multiplying the ordi-
nates of the corresponding curves in Fig. 10 by the spectral trans-
mission of a lens, the values for which were obtained from a paper by
L. A. Jones1 published in the JOURNAL.
Fig. 11 also shows the spectral sensitivity of high-speed pan-
chromatic film as given by Jones.2 The ordinates of this curve are
116 W. N. GOODWIN, JR. [j. s. M. P. E.
proportional to the reciprocals of the radiant energy required to
produce a density of unity in the developed negative.
It will be observed by referring to this curve that the human eye
is not nearly so sensitive to blues and greens as is the photographic
film. On the other hand, Fig. 10 shows that the photronic cell is
much more sensitive to these colors and also to the reds, than the
eye, and for this reason its indications in an exposure meter are
more accurate than estimates by the eye.
In order to compare estimates of exposure by the eye with those
by the photronic exposure meter for various illuminants and for
various colors, photographic intensities were computed for daylight
(mean noon sun), tungsten illumination at 3000 °K., and for four
representative colors in monochromatic light — blue at 470 m/z,
green at 520 mju, yellow at 580 mju, and red at 650 mju. The photo-
graphic intensities were computed for two conditions: (1) for equal
indications on the photronic exposure meter, and (2) for equal
visual intensity, that is, as judged by the eye by photometric methods
or otherwise.
The photographic intensities of the light for the same indications
on the exposure meter from mean noon sun and from tungsten at
3000°K. for high-speed panchromatic film were determined by
multiplying the ordinates of the spectral energy curves by corre-
sponding ordinates of the spectral sensitivity of the film in Fig. 11
and integrating. For monochromatic light, the intensity of the
radiation, at the desired wavelengths, required to produce the same
indication on the exposure meter as for mean noon sun of the spectral
energy level in Fig. 11 used as a standard, was determined by di-
viding the photographic intensity of mean noon sun as computed
above, by the ordinate of the photronic photoelectric cell response
curve at the desired wavelength; then multiplying the radiation
intensity thus obtained by the sensitivity ordinate at that wave-
length of the spectral response of the film.
The photographic intensity for the same visual intensity is de-
termined in the same manner as that just described for equal pho-
tronic exposure meter indications, except that instead of using the
photronic cell response curve, the visibility or eye response curve is
used. The results are tabulated in Table II, and give the ratio of
the amount of radiation at each wavelength to that which will
result in a film density of unity, compared with daylight as a stand-
ard. For example, estimates by the eye for blue will give an ex-
Feb., 1933] PHOTRONIC EXPOSURE METER 117
posure four times the correct value, and for yellow slightly over
!/4, or a range of about 16 to 1 in a scene; whereas the photronic
exposure meter gives nearly correct values for the blue and red and
half or slightly less for the yellow and green, or a range of about
2 to 1 in a scene.
TABLE II
Photographic Intensity Resulting from Exposure as
Determined by
Color or X Photronic
Source m/a Eye Exposure Meter
Daylight ... 1.0 1.0
Tungsten ... 0.81 0.81
Blue 470 4.0 1.1
Green 520 0.35 0.53
Yellow 580 0.27 0.41
Red 650 2.5 1.1
Monochromatic light is, of course, not found in ordinary scenes,
as the colors of natural objects are composite, consisting of rather
wide wave-bands and usually having a large proportion of white
light. The colors selected, however, are sufficiently representative
of the visible spectrum to illustrate the difference in results obtained
by the two methods. They show that the photronic exposure meter
gives indications that, considering the latitude of films, differ rela-
tively little from the true values throughout the spectrum, whereas
the eye values vary through such a wide range that they illustrate
again how poor the eye is as a means of estimating exposure, even
with the assistance of the usual photometric methods.
FILM SPEEDS
The exposure meter calculator and film speeds are based upon
illumination equivalent to average daylight. For other luminous
sources the film speeds may be considered as having different values
corresponding to the source, the kind of emulsion, and the spectral
response of the photronic photoelectric cell, and the calculator may
be set to these values.
Owing to the spectral response characteristic of the cell, the speed
values to be used with the meter for various illuminants will, in
general, not correspond to the relative sensitivities of the emulsion
as supplied by the manufacturer of the film, as these are based upon
equal visual intensities or upon equal radiant flux. However, as
stated above, the speed values for average daylight and tungsten
at 3000 °K., by a happy coincidence, do correspond.
118 W. N. GOODWIN, JR.
In a similar manner when filters are used they may be considered
as changing the film speed by their multiplying constant and the
calculator may be set accordingly.
In Table III are listed arbitrary speed numbers for various types
of film, gathered from various sources and from tests, that are the
best obtainable at the date of this writing. They are based on the
speed of high-speed orthochromatic film, which is given the number
16. These values may require modification as a result of further
experience. A very excellent contribution to this subject was made
by Davis and Neeland in this JOURNAL.3
TABLE III
Film Daylight Tungsten
Ordinary Amateur 12 4
Verichrome or Plenachrome 16 6
Regular Cine Kodak Panchromatic 12 6
Super Cine Kodak Panchromatic 16 12
Commercial Panchromatic 16 8
Super Panchromatic 24 16
The author wishes to acknowledge the helpful assistance of L. A.
Jones, of the Eastman Kodak Company, and of D. R. White, of the
Du Pont Film Manufacturing Corporation, in developing experi-
mental films under controlled conditions, and for suggestions referred
to above.
REFERENCES
1 JONES, L. A.: "Photographic Sensitometry, Part I," /. Soc. Mot. Pict.
Eng., XVII (Oct., 1932), No. 4, p. 491.
2 JONES, L. A.: "Photographic Sensitometry, Part IV," /. Soc. Mot. Pict.
Eng., XVIII (March, 1932), No. 3, p. 324.
3 DAVIS, R., AND NEELAND, G. K. : "Variation of Photographic Sensitivity
with Different Light Sources," /. Soc. Mot. Pict. Eng., XVIII (June, 1932), No.
6, p. 732.
MUSICAL ACOUSTICS OF AUDITORIUMS*
PETER CAPORALE**
Summary. — The author proposes that, on account of the variation in the time
between beats in music, more effective rendition of music could be accomplished by
varying the time of reverberation of the auditorium or room in which the music is
played. The relation between the tempo of the music and the time of reverberation
is discussed, with particular reference to the overlapping of the reverberation from
one bar of music to the succeeding bar. (Editor's note: The reader is cautioned to
distinguish between the technical meanings of terms used in the paper and their
meanings in musical parlance; the footnotes should be consulted for the musical
acceptations.)
The importance of increasing the usefulness of enclosures such as
sound motion picture studios, recording studios, broadcasting studios,
theaters, music halls, etc., by controlling the time of reverberation
is being recognized more and more. In all these types of rooms
music of some form is performed, and the control of reverberation
may add considerably to the artistic presentation of such music.
Thus, the effects of large tone or fine definition or articulation may
both be achieved by suitable control. The following is a brief dis-
cussion of some of the important factors to be considered in con-
trolling reverberation for musical purposes.
Music is a unique art in that a third person (or group of persons)
is necessary to convey the composer's thought to his audience. In
particular cases it may happen that the third person and the composer
are one, as, for example, when Kreisler plays his own compositions.
But even in these cases Kreisler the violinist is not the same as
Kreisler the composer. In other words, composition and expression
are neither the same nor are they simultaneous. To speak of this
situation in more familiar engineering terms, we may think of the
history of a musical composition as divided into four stages. The
first, which we shall call A, is the conception of the composition in
the mind of the composer. The second, B, is the transcribing of this
* Received December 15, 1932.
** Electro-Acoustical Engrg. Co. of America, Philadelphia, Pa.
119
120
PETER CAPORALE
[J. S. M. P. E.
concept into a form known as the score. The third, C, is the trans-
ference of the concept from the score to the mind of the player, or
interpreter; and the fourth, D, the transmission of the concept, by
means of sound, to the audience. It must be obvious that in such a
complex transition it is rare that a listener will sense the same musical
thought (i. e., the same physical sound as conceived originally) that
the composer had in mind, and we may therefore speak (rather
loosely, of course) of the efficiencies of the various stages of the transi-
tion. For example, there are some effects that can not be indicated
by the usual musical notation; hence the efficiency of transition B is
less than unity. Similarly, the score may be ambiguous in certain
3.6
Aaigi
FIG. 1. Duration of musical beats for various metronome settings
(Metronome de Maelzel).
parts, or in some respects ; therefore, the efficiency of transition C is
also less than unity. Very little has been done to increase these
various efficiencies. Reverberation control, however, offers the
possibility of increasing the efficiencies of both transitions B and D.
The combinations of sound that reach the audience are determined
not only by the nature of the source of the sound (orchestra, organ,
violin, etc.} but also by the character of the enclosure within which
the sound occurs and the audience is located. This fact has been
known from the most ancient times, but no direct use was made of
the knowledge. For instance, when Bach wrote the Mass in B-minor
he was acquainted quite intimately with the acoustical properties of
Feb., 1933] ACOUSTICS OF AUDITORIUMS 121
the Leipzig Thomaskirche and could foresee the approximate effect
of the music. It was obviously impossible for him to foretell the
effect in some other church or auditorium. Recent progress in
acoustics, particularly as regards reverberation, has made it possible
to control the acoustical properties of an auditorium so that a musical
composition may be rendered in such a manner as to accord very
closely with the wishes of the interpreter. Furthermore, the control
of the auditorium might be placed in the hands of the composer, so
that not only is efficiency D increased, but also that of B; or, more
specifically, the composer might indicate on the score just what the
acoustical conditions should be for any particular passage.
The technical problem of controlling reverberation is this: given an
auditorium having a certain volume and exposed wall surface, to
vary the total sound absorption of the room so as to vary its period of
reverberation. Several times the idea has been suggested,1 and in
fact, a definite system has actually been proposed, whereby various
surfaces of different coefficients of absorption could be exposed.2
None of these systems, however, could have been readily adaptable
to the kind of control required for musical purposes.
The realization of such a scheme, of course, would involve not
only the designing of appropriate equipment by the engineer, but,
as well, the training of the musician so that he might understand the
full possibilities of the system. The latter problem is, of course, not
of interest to us here. This discussion will be limited to the musical
requirements from an engineering standpoint. It must be noted that
in many cases it might not be practicable to vary the time of rever-
beration during the performance of a piece of music ; but it might
even then be practicable to vary it between successive pieces.
In general, musical compositions may be very roughly divisible
into two classes — solo and ensemble, each of which is further divisible
into slow and fast music. The crudity of this classification is ob-
vious, but it is at least indicative of the range of types of music.
It is rare to find rapid, brilliant passages for one instrument in or-
chestral works (with the possible exception of solos for the first
violin) . Music is, moreover, characterized partly by rhythm, of which
the elementary component is the beat.* The rapidity or slowness
of a passage depends upon the lapse of time between beats. Fig. 1
* The word "beat" must be distinguished from the common acoustical beat.
As here used it has the more common musical meaning, indicating the instant
of beginning a certain time interval in music.
122 PETER CAPORALE [j, s. M. p. E.
shows a curve indicating the duration in seconds, between beats
produced by a standard metronome. For convenience the cor-
responding musical terms are also given. Now, since the deleterious
effect of reverberation is to cause overlapping of successive sounds,
the problem becomes that of reducing the time of reverberation
sufficiently to avoid undesirable overlapping. But it must be re-
membered that not in all cases is overlapping to be completely
avoided. If successive sounds pertain to the same harmony, some
overlapping is in fact desirable. This, however, is a problem for the
composer rather than the engineer.
It will be evident from Fig. 1 that, besides ease of control ( a special
member of the ensemble may be assigned to the control box with its
own score), rapidity of control is an important factor in the design
of reverberation control equipment. Another determining factor is
range of control; and finally, the control must be silent in operation.
These factors are determined by musical requirements. There are
also the usual factors of economy of installation, operation, and main-
tenance, which determine to what extent the other requirements
can be fulfilled.
(A) Ease of Control. — Several reverberation control systems have
been proposed or tried,1'2-3 all of .which have been manually operated
devices. A notable example is the installation of the National
Broadcasting Company in its Chicago studios. It is quite evident,
however, that for our purpose we must have recourse to remote con-
trol, and by using flexible cables the control box might be one of the
instruments of the ensemble. There would thus be a musician "play-
ing the auditorium," under the supervision of the conductor. For
organs this would mean additional buttons for its already complex
control panel.
(B) Rapidity of Control. — To understand the problem fully, it
will be necessary to consider briefly the musical forms giving rise to
it. The required speed is a function, not of the rapidity of the music
itself, but of the quickness with which the tempo changes.
As has already been indicated, music is characterized among other
things by rhythm, and a composition must for this reason be divided
into beats, which are grouped into larger units called bars. It is
the latter grouping that gives to a passage a large part of its rhythmic
character. A waltz, for example, is distinguished by having three
beats to a bar, etc. But also, and more important from our stand-
point, the bar is the unit to be considered in the transition from a
Feb., 1933] ACOUSTICS OF AUDITORIUMS 123
slow to a rapid tempo or vice versa; that is to say, the tempo changes
from bar to bar rather than from beat to beat, the first beat of a bar
coming at the beginning of the bar. In other words, the tempo, or the
rapidity of succession of beats, does not usually change within the bar,
but between bars. For example, in Fig. 2 (upper chart) which is a sche-
matic indication of a sequence of bars, each having three beats a, b,
and c, we have the first two bars marked largo. From Fig. 1 we see that
the time between successive beats for this tempo is four seconds, and
hence the length of each bar is twelve seconds. The third and fourth
bars being marked allegro, the time between beats is only 0.7 second,
each bar representing, therefore, 2.1 seconds, or less than one-fourth
the duration of each of the first two bars. Similarly the fifth and sixth
bars are marked andante, with 1.2 seconds between beats and 3.6
seconds to each bar. Let us examine the conditions such a sequence
would impose on a reverberation control system.
The first two bars (largo) being very slow, the music therein con-
tained depends for its effect on largeness of tone* rather than on
rhythm. The time of reverberation should therefore be compara-
tively long.** Certainly 3 or 4 seconds (usually a large value for an
auditorium containing an audience) would not be too long for these
bars. But as soon as we get to bar No. 3 (allegro) the bar duration
becomes only 2.1 seconds, and the period of reverberation must be
reduced to prevent the successive beats from overlapping. Actually,
whether the indicated time of 3 or 4 seconds is too long or not, is
determined by the music itself. For the case referred to, this time
would cause two successive beats to overlap. This is permissible
and even desirable in those cases where the successive beats form
part of the same "harmony." In other cases, the time would natur-
ally have to be shorter. The time mentioned, however, is intended
only to indicate the possible range, and is not necessarily correct
for all music marked largo. The actual value must be determined by
* Largeness of tone is concerned mainly with amplitude of sound as opposed to
rhythm. A full definition would involve considerations of musical tradition and
custom, as well as an analysis of psychological reaction to sound. Largeness of
tone involves not only the amplitude of the sound, but the wave-form as well.
Thus, we hardly speak of the largeness of tone of the oboe, or tympani, or cym-
bals; but we do speak of the largeness of tone of a cello or bass viol, or of the
viola, or violin, or of some of the wind instruments. The vernacular of music
contains many terms that are perfectly clear to musicians, but yet defy simple
and concise definition for the layman.
** In such cases, the harmony also warrants long reverberation time.
124
PETER CAPORALE
[J. S. M. P. E.
the composer who has been taught reverberation control and its
principles. In addition, it must be remembered that as the duration
of a bar decreases, the music usually depends more and more on
rhythm and definition. This requires a still shorter reverberation
time, and for bars No. 3 and No. 4 its value will have to be of the
order of 0.5 second for best effects. In bars No. 5 and No. 6 we are
again permitted to increase the reverberation time, but in this case
to about 1.25 seconds (the optimum in all cases will obviously de-
pend upon the nature of the music itself). There is one difference
between these two changes. In changing from bar No. 2 to bar No. 3
we had to make the change before the beginning of the third bar
Bar No.
Beat
Time Between \
Oftfjf c
Duration of
Bar-
Tempo
b c a b
I M I N I M I N I N I bl &
_ /* J, /^ _v.j_ 27 . _ 2./ i^_ 3.6 vl 3.5 J
ifftf. Sec sec sec. sec 'p Sec.
U Largo n Allegro >< Andante M
I
FIG. 2. Above: chart showing the relation between the intervals between
beats and the duration of the bar for different tempos. Below: chart indicating
the manner of changing the time of reverberation when the tempo is changed.
to avoid bad effects in the more rapid passage. This means that the
end of bar No. 2 must be borrowed for this change, and if the change
can be made in 2 seconds it will not be noticeable (the duration of
the last beat of bar No. 2 being 4 seconds) . In changing from bar No.
4 to bar No. 5 we should, analogously, borrow time from bar No. 5
which is slower; but it is a fact that most music is so arranged that
the transition from a rapid to a slower tempo is never sudden,
passing through a rallentando or gradual slowing up. Hence, the
conditions imposed by this change are never severe, time being avail-
able from both bars. Since the power requirements of the control
system are determined by the rapidity of the control, we may say
Feb., 1933]
ACOUSTICS OF AUDITORIUMS
125
that it is the change from slower to more rapid tempo that is the
controlling factor. From a consideration of the musical literature we
may state that the time of change from maximum to minimum rever-
beration should approach, as a working value, one second. It is
evident that economic considerations will determine how closely
this value may be approached ; a slower control will not be a serious
handicap except in certain special musical forms. Fig. 2 (lower chart)
shows the same sequence of bars of Fig. 2, with the reverberation time
indicated, and a possible way of indicating the interval over which
the change may be effected.
(C) Range of Control and Silence of Operation. — This is a subject
that always arouses comments due to the contradictory require-
.3 .4- .f .6
Volume of Room in Million Cx Ft.
FIG. 3. Approximate relation between size of orchestra and vol-
ume of auditorium (from information given in Circular 300, U. S.
Bureau of Standards, 1926). 4
ments of large tone and good articulation. The writer's experience
with outdoor concerts, however, has shown beyond a doubt that
maximum absorption is most desirable for passages requiring good
articulation. In general such passages do not require large tone but
only crispness and brilliance. The ill effects of open-air theaters are
evident only in slow movements where the chief emotional medium is
tone. For a given size of auditorium the maximum value of rever-
beration time will be limited by the audience, the orchestra personnel,
and the wall surfaces; similarly, the minimum value will be limited
by the maximum obtainable absorption in the given volume, though
this lower limit is less definite than the upper limit. These limits
prevent the same absolute range of control from being applicable
126 PETER CAPORALE [j. s. M. P. E.
in all cases. However the control equipment should be calibrated in
time units for uniformity and to minimize troubles in scoring.
Most concert halls designed for the same size of orchestra should have
similar characteristics ; hence, the above-mentioned limitations imply
simply that the scoring for the control should depend on the size
of orchestra, just as at present there are different arrangements of the
same composition for different sizes of ensembles. For convenience
the approximate relation between the size of orchestra and the
volume of the auditorium is shown in Fig. 3.4
One thing is to be pointed out relative to this use of reverberation
control. It is the use of absorbents having approximately flat fre-
quency characteristics. In other words, if a control key represent a
reverberation time of T\t say, for the notes of a piccolo, it must
represent the same time* for the notes of a bass tuba or a bass viol.
If this is not the case, it is possible to score correctly provided the
actual frequency characteristic is known, but this introduces undesir-
able complications, inasmuch as two halls possessing different
frequency characteristics would require separate scoring.
The silent operation of the equipment is, of course, necessary to
avoid disturbing or distracting factors during the rendition, and is an
end to be attained through the proper mechanical design of the
system and the proper sound-proofing of the prime movers.
Use of Reverberation Control for Solo Work. — It has already been
pointed out that, except for organs, the instantaneous control of
reverberation by instrumental soloists is impracticable. The best
that can be done in such cases is to provide the best average reverbera-
tion time for the given composition; this is a problem for the musi-
cian, not the engineer. It is interesting to the latter to know, how-
ever, that having met the requirements already outlined, he will have
covered the requirements for solo work which, therefore, does not
require his special attention.
* Note that this does not refer in the least to the desirable characteristic of an
auditorium having no reverberation control. Several investigators have al-
ready studied this problem. What is referred to here is the fact that a given key
or switch on the reverberation control box must, if it is marked T\, produce that
reverberation time under any circumstance. If then, it is desirable to have a
reverberation time, T\, for the bass viol, and a time, T2, for the piccolo (other condi-
tions being equal) then, that means that T2 should be called for when the piccolo
is playing and T\ when the bass viol is playing. The case of ensemble is more
complex, and as to what is the optimum time for a given passage involving cer-
tain given instruments is a problem to be analyzed separately.
Feb., 1933] ACOUSTICS OF AUDITORIUMS 127
Conclusions. — To sum up the basic requirements for a reverbera-
tion control system for the continuous control of auditorium acoustics
from a musical standpoint, we have:
(a) Ease of operation.
(b) The time required to pass from maximum to minimum
reverberation should approach one second; a value less than this
would impose too severe economic requirements.
(c) The range of control should be a maximum, and be covered
by steps, the number of which should be experimentally determined.
(d) The operation of the equipment must produce no disturbing
or distracting noises.
REFERENCES
1 KNUDSEN, V.: "Architectural Acoustics," John Wiley & Sons, New York,
1932, p. 413.
2 PETZOLD, ERNEST: "Regulation of Acoustics of Large Rooms," /. Acoustical
Soc. ofAmer., HI (Oct., 1931), No. 2, p. 288.
3 EBERT, SYLVANUS J.: "Design and Acoustics of Broadcast Studios," Radio
Engineering (Jan., 1932), p. 13.
4 HEYL, P. R. : "Architectural Acoustics," U. S. Bureau of Standards, Circular
300, 1926.
A NEW WESTERN ELECTRIC DOUBLE FILM PORTABLE
SOUND RECORDING SYSTEM*
C. R. DAILY**
Summary. — A description is presented of a complete new Western Electric double
film portable recording system recently perfected by Electrical Research Products,
Inc. The equipment is mounted in a trunk and is designed to be used for location,
industrial, and educational recording where portability is of the utmost importance.
Entirely new designs of the system amplifier, noise reduction unit, d-c. interlocking
motor system, double film recorder, and other units liave been perfected. The im-
proved moving coil microphone, permanent magnet light valve, and many other
recent equipment developments have been used. The minimum weight of the simplest
sound recording channel of this new type is approximately 325 pounds. By adding
other units, sound recording systems of any degree of elaborateness may be established.
Portability and reliability of picture and sound equipment de-
termine the limitations of the talking picture screen. While the
field of action of the motion picture camera is practically unlimited,
its usefulness has been materially enhanced by the development of
highly portable sound equipment. The first sound recording chan-
nels used on location consisted of apparatus of the fixed-channel
type remounted and placed on trucks. Such channels, while very
useful, clearly demonstrated the need of still lighter and more port-
able equipment. Later came the channel consisting of individual
units mounted in trunks, which could be used on locations not
accessible to the sound truck. The latter form of equipment has
proved to be more generally useful and for that reason has been
more intensively developed than any other.
This paper presents a description of a new double film trunk
channel for recording which, on account of its light weight and ease
of operation, overcomes the many objections found in earlier designs
and fills a very definite need on the part of the studios and others
who have need of portable sound recording facilities of the most
advanced design and highest order of flexibility.
* Received November 30, 1932.
** Electrical Research Products, Inc., New York, N. Y.
128
NEW SOUND RECORDING SYSTEM 129
Some of the new developments that have made possible the
design of this improved channel are as follows: The moving coil
microphone is lighter, more sensitive, and less subject to adverse
weather conditions than the condenser type of transmitter. The
permanent magnet light valve and modulator unit are much smaller
and more sensitive than the light valve assemblies formerly used, and
have made possible a much lighter and more compact amplifier
and battery assembly. The entirely new d-c. interlocking motor
system requires a minimum of power to operate, and provides
reliable speed control for all cameras and recorders. New and
lighter transformers have reduced the weight of the speech system,
while new vacuum tubes have increased the carrying capacity and
reliability of operation of the amplifiers, at the same time allowing
for a considerable reduction in both A- and 5-battery consumption.
Improvements made in the noise reduction amplifier and control
unit materially reduce the weight of this part of the equipment.
GENERAL DESIGN FEATURES
A strong, but light, welded duralumin case is used to contain this
new trunk channel, each complete case weighing less than 90 pounds.
Specially impregnated insulation has been used in the wiring to
prevent deterioration in warm, humid climates. Considerable
care has been taken to reduce the number of connections and simplify
the control, and yet assure ease of set-up and reliability of operation
in the field.
A complete sound recording channel consists of four distinct
groups of equipment: sound pick-up devices, amplifiers, film re-
corders, and motors, with their associated sources of power. The
details of design of each of these units have been carefully studied
and the operation of the assembly of units considered as a whole so
that a unified system could be provided.
The following tabulation lists the various units that have been
designed for these recording channels. Several groupings of equip-
ment are mentioned in order to illustrate the flexibility of the channel
in building up systems to meet varying recording needs:
1. Pick-Up Devices
(a) One or two moving coil transmitters connected directly to the main
amplifier. Either transmitter may be used at a time. No external
transmitter amplifiers required.
130 C. R. DAILY [j. s. M. P. E.
(b) One or more moving coil transmitters or condenser transmitters
with single- or two-stage transmitter amplifiers connected to an
extension 3-dial mixer and volume control cabinet. This mixer
connects by cable to the main amplifier.
2. Amplifiers
(a) The main amplifier provides in one cabinet all the gain required for
the operation of this channel with a single moving coil microphone
pick-up.
(&) The same amplifier is also used with the extension mixer mentioned
above for multi-microphone pick-up and mixing.
(c) The noise reduction amplifier and control unit derives its input from
the film recorder and may be used if desired.
3. Film Recorders
(a) A new film recorder using the permanent magnet light valve and
carrying the necessary lamp controls and motor switches is available
for the double film channel. Split beam photoelectric cell monitor
is available with this recorder.
4. Power Supply
Three fundamental motor systems are available for use with this channel :
(a) Standard interlocking motors to be used with the present distributor
system.
(&) A new type of double wound d-c. interlocking motors with manual
speed control. Speed may be controlled automatically by adding a
special control cabinet and a generator-distributor case. A maxi-
mum of three picture cameras and the film recorder may be used
with this system. Twelve- volt storage batteries are the only source
of power required.
(c) Synchronous induction motors operating from a 50- or 60-cycle, 3-
phase, 220-volt power supply.
Fig. 1 shows the simplest arrangement of the double film recording
system. A moving coil microphone, amplifier, film recorder, camera,
two motor switch boxes, three 12-volt battery boxes, and the necessary
cables make up the entire channel. The speed of the interlocking
double wound d-c. motors is manually controlled. The sound
equipment by itself weighs approximately 325 pounds, and the
picture camera and its tripod, motor, battery, and cable, 170 pounds,
making a total of 495 pounds. Additional cameras may be used
with this set-up if desired.
Fig. 2 shows a more elaborate double film recording channel
having an extension mixer for three-microphone pick-up and mixing,
order wire, photoelectric cell monitor, and provision for automatic
speed control of the motor system of the film recorder and one or
Feb., 1933]
NEW SOUND RECORDING SYSTEM
131
more cameras. This form of the channel would be satisfactory for
heavy duty location work with a large company. The speech
equipment and motor system complete weigh approximately 850
pounds, while the cameras and their auxiliary equipment weigh,
as mentioned before, about 170 pounds each. This channel is
shown in schematic form in Fig. 3. As each case weighs less than
90 pounds when ready for shipment, even this elaborate system
may be quickly packed on a truck and taken on location. The
FIG. 1. Minimum complete double film recording system.
entire system may be unpacked and made ready for operation in
less than ten minutes by two or three men.
Other arrangements of the equipment are possible, those just
described being shown as examples of the flexibility of operation of
the system. Thus, wide-range film recording is effected by adding
the necessary units of equipment to the system by means of jacks
provided in the portable trunk units. All plug and jack connections
are clearly marked to facilitate setting up the equipment in the field.
132
C. R. DAILY
[J. S. M. P. E.
A brief description will now be given of each of the component
parts of this system.
MAIN AMPLIFIER
The amplifier used with this channel is entirely new in design and
construction, and has a minimum weight and power consumption.
Fig. 4 shows a front view of the case, which is 12 inches deep and has
a front panel 19 inches wide by 12 inches high. It weighs 80 pounds
FIG. 2. Double film recording system with extension mixer, noise reduction,
photoelectric cell monitor, order wire, and automatic speed control.
complete with B and C batteries. The shape of this case has been
made standard for practically all units of the channel so as to facilitate
stacking of equipment. Fig. 5 shows the internal construction of
the amplifier.
The speech input to the amplifier is normally taken from the
output of one of the new moving coil microphones,1 obviating the
necessity of using a separate transmitter amplifier and polarizing
battery. This type of transmitter may be used in humid climates
and requires no special precautions such as were required with the
Feb., 1933]
NEW SOUND RECORDING SYSTEM
133
condenser type. This feature should appeal to the sound man who
is required to go to locations having difficult climatic conditions.
The maximum gain of the amplifier is approximately 104 db.,
which is sufficient to modulate fully a permanent magnet light valve
used for recording speech out-of-doors at distances of 15 feet to
30 feet from the moving coil transmitter. A volume indicator and
headphones are provided for monitoring.
The block of B batteries mounted in the main amplifier will
operate this amplifier for fifteen to twenty hours, after which it can
be easily replaced. This battery life is sufficient for several days'
FIG. 3. Schematic diagram of double film recording system.
operation. The filament supply is obtained from the exciting lamp
storage battery. A very desirable feature of the system is the fact
that the amplifier may be located as far as 400 feet from the recorder
and its associated 12- volt lamp battery, as a voltage of only 4.5 is
required at the filament terminals. It is also possible to use a cable
between the moving coil transmitter and the amplifier 100 feet to
300 feet long, so that a very wide field of operation may be covered.
A special jack is provided for local external A and B batteries,
providing for the use of heavier duty B batteries when operating on
locations where extreme portability is not required. A special
external 5-battery box for the main amplifier and extension mixer
134
C. R. DAILY
[J. S. M. P. E.
is available, providing for two sets of 135-volt batteries having a
useful life in excess of 100 hours.
The Western Electric 264-^4 vacuum tube is used for all speech
transmission services in the system, thereby reducing the number
and types of tubes that would normally be carried. Eight of these
tubes are used in the main amplifier, the total filament current of
which is only 0.9 ampere at 4.5 volts, the total plate current being
only 12 milliamperes at 135 volts. These values of filament and
plate current represent a considerable reduction from those found
in earlier systems, and will assist particularly on expeditions where
every pound of weight must be considered. A separate B battery
is not required for the internally mounted transmitter amplifier;
FIG. 4. Portable system amplifier, front view.
this omission effects a considerable saving in weight and maintenance.
Provision has been made for directly reading the filament voltage
and plate current of each tube. A jack and key are mounted on the
amplifier so that external high- or low-pass filters or equipment for
wide-range recording may be connected in the circuit if needed. A
speech equalizer is mounted in the main amplifier and can be con-
nected to the circuit by a key. An order wire sub-set has been
mounted in the amplifier so that the recordist and extension mixer
may communicate with each other.
If pick-up from more than one microphone is required, a simple
switching arrangement allows for the alternative use of either of
two moving coil microphones. If mixing facilities are required
Feb., 1933] NEW SOUND RECORDING SYSTEM 135
for several microphones, an extension mixer case is used, which
connects directly to the main amplifier by means of two cables.
EXTENSION MIXER
The extension mixer case is designed to operate from the output
of one, two, or three single- or two-stage transmitter amplifiers
using either condenser or moving coil microphones. Three mixer
dials, a single-stage booster amplifier, a volume control potentiometer,
a filter jack, a volume indicator, a headphone monitor extension,
and an order wire are provided. The A -battery supply is provided
by the lamp battery, while the required B- voltage is supplied from a
separate battery box connected at the main amplifier.
NOISE REDUCTION AMPLIFIER AND CONTROL UNIT
The value of noise reduction has been clearly demonstrated during
the past year. The standard studio type of equipment was de-
FIG. 5. Portable system amplifier, interior view.
scribed before the Society of Motion Picture Engineers in October,
193 1.2 An entirely new design for noise reduction equipment, how-
ever, has been worked out for this portable channel. The principal
object in designing a new noise reduction circuit for location service
was to reduce materially the weight of this important piece of equip-
ment. A gross weight of only 68 pounds, including tubes and B
and C batteries, has been achieved with no sacrifice in quality.
Filament power is obtained from the 12- volt lamp battery, only
0.6 ampere being required. The total plate circuit drain is ap-
proximately 18 milliamperes under normal operating conditions,
and is provided by a 135- volt block of B batteries mounted within
the case. One block of these batteries will operate the unit for ten
to fifteen hours. These blocks of B batteries are interchangeable
136
C. R. DAILY
[J. S. M. P. E.
with those used in the main amplifier, and may be replaced as a unit
in a few minutes. External B batteries may be used if desired.
The filament voltage, plate current of each tube, and light valve
bias current can be read directly.
Both the noise reduction amplifier and light valve control unit
have been mounted in one case, and have been so arranged that the
necessary adjustments may be made very quickly, thereby facili-
FIG. 6. Film recorder.
tating the line-up of the channel for operation in the field, particu-
larly in cases where it is necessary to get into action in a very short
time.
A 1000-cycle oscillator is mounted within the noise reduction
case, and is used to adjust the noise reduction unit for cancellation
of the bias current and to determine the overload point of the light
valve. The oscillator also provides a useful source of tone for
general testing purposes.
Feb., 1933]
NEW SOUND RECORDING SYSTEM
PORTABLE FILM RECORDER
137
An entirely new design of film recorder is used in this channel.
A front view of the recorder with the door of the camera and modu-
lator unit open is shown in Fig. 6. The mechanism is mounted in a
casting not much larger than a standard motion picture camera and
is placed on top of the duralumin base which contains the necessary
controls for the recording lamp, light valve, photoelectric cell moni-
toring apparatus, order wire sub-set equipment, and switches for
the motor system. The camera has been designed so that the door
can not be closed if any of the guide or tension rollers are not in
their proper positions.
A new permanent magnet light valve, recently perfected by the
Bell Telephone Laboratories, is used in this recorder. Its use makes
FIG. 7. Photoelectric cell monitor and storage case.
possible a considerable reduction in the size and weight of the re-
corder, and since it is more sensitive than the standard studio type
of light valve, it is possible to reduce materially the battery drain
of the main amplifier by using output tubes of lower current ca-
pacity than formerly.
The sprocket that pulls the film past the modulated light beam
has been carefully filtered. An aperture of the roller gate type is
used, and has proved to be very satisfactory. This aperture was
first used in the Western Electric studio reproducing machine,3
and possesses many advantages over the sliding gate formerly used.
A tension roller also helps to assure evenness of motion of the film
past the light gate.
Photoelectric cell monitoring may be used if desired, since a
deflecting mirror is mounted in the modulator so that the modulated
138 C. R. DAILY [j. s. M. p. E.
light that does not fall upon the objective lens is reflected to a caesium
oxide photoelectric cell. The output of this cell is connected to a
single-stage amplifier and a pair of headphones. The output trans-
former and 90-volt B battery for this amplifier are mounted in an
auxiliary case, shown in Fig. 7. This auxiliary case connects to
the recorder by a short cable, and is used also for storage of some of
the motor control units, headsets, handsets, spare light valves,
microscopes, tubes, etc.
The output of the photoelectric cell amplifier or the direct monitor
FIG. 8. Motor control cabinet and speed control motor.
may be patched to an auxiliary amplifier to provide loud speaker
monitoring facilities if desired.
MOTOR SYSTEM
Standard interlocking, synchronous, or the new double wound
interlocking d-c. motors may be used with this sound recording
system. The following section outlines the general operating features
of each of these motor systems.
D-C. Interlocking Motors. — A new design for the d-c. interlocking
of motors has been perfected. The 3-phase winding on the armature
and a special type of field construction eliminate hunting and over-
come the irregularity formerly experienced with this type of motor
Feb., 1933]
NEW SOUND RECORDING SYSTEM
139
system. Interlocking action between these motors is very positive,
but is so designed that it is impossible to burn out the armature or
cause destructive arcing of the commutator due to an out-of-phase
condition when starting or throwing additional motors on the line.
A single 12- volt storage battery is the only source of power required
for each motor. By proper design, the danger of burning the com-
mutator at this low voltage has been eliminated and very reliable
operation of the motors obtained.
With the double film system and manual speed control, one
battery is used for the amplifier, one for the recorder motor, and
FIG. 9. Cases for 12-volt batteries.
one for each camera that may be required. Thus, the power system
can be readily expanded to meet production requirements.
A small switch box containing a field rheostat, relay, and three-
position switch is associated with each motor. If the switch is
thrown to the "non-synchronous" position each motor may be run
independently of the others. This arrangement permits the taking
of silent shots at any speed and for the photographing of numbering
slates. If the switch is operated to the "interlock" position, all
motors in the system may be started simultaneously from any one
motor. An "off" position is also provided so that any motor may
be readily disconnected from the line.
140 C. R. DAILY [j. s. M. P. E.
Three methods of speed control are available for use with the
double wound d-c. interlock system. The simplest is manual control
of all motors by the recordist, who adjusts and maintains the speed
of the system by means of a rheostat while observing a tachometer
mounted on the recorder.
Automatic speed control using the same d-c. motors may be
obtained by adding a special control cabinet and speed control
motor. These units are mounted in separate cases weighing about
55 and 70 pounds, respectively, and are shown in Fig. 8. A 12-volt
storage battery for each unit is required to operate this system, and
the speed control is equivalent to that obtained with the permanent
channel distributor system installations.
Another method of using these d-c. motors is to connect the inter-
lock windings to a public service company's 3-phase, 220-volt line
to provide interlock while the power to drive the motor is still pro-
vided by 12-volt batteries. Thus synchronous operation is obtained
and the speed control is quite satisfactory.
Synchronous Motors. — A second type of motor system involves
the use of 3-phase induction synchronous motors designed to
operate from a 220-volt supply. For portable use this supply may
be derived from either the public service lines or from a portable
d-c. to a-c. motor-generator set which is available. The d-c. motor
of the generator-set operates from a 36-volt battery comprised of
three standard 12-volt batteries connected in series, the generator
delivering 3-phase power at 220 volts. With this method of drive
the motor speed is a direct function of the speed of the motor-gen-
erator set which is controlled manually.
Standard Interlock Motors. — In existing fixed channels a motor
system of the interlocking type has been supplied, which can also
be used to drive the recorder and cameras of the portable channel.
Standard interlocking motors with special adapters have been built
so that they may be connected directly to existing studio motor
lines and distributors.
With the three motor systems that are available it is possible to
meet any field recording condition. The primary power may be
either 12-volt d-c. or 3-phase, 220-volt a-c. The alternating
current may be generated either locally or taken from a 220-volt
supply line. Speed control may be either manual or automatic,
depending upon the requirement of the material that it is desired
to record.
Feb., 1933] NEW SOUND RECORDING SYSTEM 141
MOTOR BATTERIES
Consideration was given to the idea of using 135-volt, heavy duty
B batteries to drive the motors when used on location, but it was
found that 48 pounds of these batteries would not have sufficient
power to pull more than 6000 feet of film through the recorder.
Therefore, the replacement and expense of this type of battery would
be a major problem on an expedition. The decision to use single
storage batteries of the 12- volt, 36-pound airplane type for each
motor materially simplifies the field requirements and provides at
the same time sufficient power to run over 8000 feet of film without
recharging. This battery life corresponds to at least two days of
normal operation on location. The batteries are mounted in a
duralumin carrying case equipped with a connecting cable and jack.
The weight per unit is only 51 pounds. A view of one of these
battery cases is shown in Fig. 9. The same type of battery is used
for all services in the channel, such as lamp and amplifier filament
current supply. A heavier duty battery of the same type is also
available. A compact gasoline motor and direct coupled d-c.
generator weighing approximately 120 pounds is available for
battery charging and will enable the d-c. interlocking system to
operate continuously in the field without requiring replacement of
batteries.
In conclusion, it can be stated that there has been made available
an entirely new group of sound recording units that are capable of
meeting practically any requirement imposed on a double film
recording system. The various assemblies are light in weight and
are of such rugged construction that they may be readily transported
to any desired location. The quality of recording obtained with the
equipment is equivalent to that obtained with the best fixed channel
installations now in service.
REFERENCES
1 JONES, W. C., AND GILES, L. W.: "A Moving Coil Microphone for High
Quality Sound Reproduction," /. Soc. Mot. Pict. Eng., XVII (Dec., 1931), No. 6,
p. 977.
2 SILENT, H. C., AND FRAYNE, J. G.: "Western Electric Noiseless Recording,"
/. Soc. Mot. Pict. Eng., XVIII (May, 1932), No. 5, p. 551.
3 KUHN, J. J.: "A Sound Film Re-recording Machine," /. Soc. Mot. Pict.
Eng., XVII (Sept., 1931), No. 3, p. 326.
ENGINEERING AND SCIENTIFIC CHARTS FOR LANTERN
SLIDES
The following material dealing with the principles relating to the control of the
effectiveness of graphical presentation of engineering data is abstracted from the
American Recommended Practice on the subject which was approved by the Ameri-
can Standards Association on Nov. 11, 1932 (ASA Z15.1 — 1932). The standard
prepared by a sub-group of the sub-committee on Engineering and Scientific
Graphs of the Sectional Committee on Graphical Presentation, under the procedure
of the American Standards Association, 29 W. 39th St., New York, N. Y. The
American Society of Mechanical Engineers took the official leadership in the devel-
opment of this project. The original draft was presented before the American
Society of Mechanical Engineers in December, 1931.
The recommended practices given below relate to engineering and
scientific charts prepared for use as lantern slides. Although cer-
tain general principles apply to the entire field of graphics, including
time-series charts, computation charts, illustrative diagrams, etc., no
attempt is made here to cover such a broad field. Instead, atten-
tion has been directed chiefly to general*'1 and specific suggestions
applying to the most common variety of engineering and scientific
charts — line charts that show the relation between two variable
quantities.
Charts made in accordance with these recommendations are suit-
able for use as lantern slides, when reduced to one-third their original
dimensions. With slight modifications as to line widths,2 these
recommendations are also usually applicable to charts prepared for
use both as lantern slides and as illustrations for publication.
GENERAL
(1) An engineering or scientific chart shown on a lantern slide
is only an illustration, presupposes explanation by the speaker, and
usually can not be complete in itself.
(2) It should present one central idea, and should be free from
all lettering and lines that are not essential to a clear understand-
ing of its message. The number of words on the chart should be
held to a minimum (a useful rule is to aim at a total of not more than
15 words, or not more than 20 words if there is a title).
(3) Supplementary data or formulas should not be shown unless
* For reference notes see pages 148 and 149.
142
CHARTS FOR LANTERN SLIDES
143
absolutely necessary, in which case they should be isolated in posi-
tion and enclosed by a light line border.
(4) Proportions of about 7 by 10 are suggested3 for the over-all
dimensions of lantern slide charts. In choosing between a vertical
and a horizontal rectangle, consider which one presents the material
more effectively.
(5) When the amount of lettering is held to a minimum, verti-
DEFLECTION IN MILS
^o — ro c*> *k tn o ^
1
HARD RUBBER ^-
—
. '—
- —
J3
x*^
V
^- •
PHENOL
__
FIBRE
"
^HMIN|HBMMMB|HMHMMMM
_— — w
?
) 20 40 60 80 100 12
TIME IN HOURS
V
FIG. 1. Original chart for lantern slide (9 X 63/s in., including margins);
exactly 1/2 actual size.
cal Gothic capitals are recommended as being highly legible and
easy to construct. (See accompanying charts.)
For the average lecture hall or auditorium, legibility throughout
the hall is obtained4 if the smallest lettering on the slide consists of
capital Gothic letters 0.040 inch to 0.045 inch high, having a line
width of about 0.006 inch. It is recommended that in preparing
charts for lantern slide use, the original chart be made three tunes
the final lantern slide size, in which case the smallest letters should
be made about one-eighth inch high with a line width of about 0.017
inch.5 (See Figs. 1 and 2.)
144
CHARTS FOR LANTERN SLIDES
[J. S. M. P. E.
For charts with very little lettering that are not to be used for
publication, a somewhat larger size of letter is suggested.
(6) In general, a satisfactory lantern slide can be produced by
using lettering of substantially the same size throughout. Titles,
if included, should be made slightly larger.
(7) All lettering and numbers on a slide should be placed hori-
zontally, if practicable. Any lettering or numbers for which this is
not practicable should face toward the right-hand side of the slide.
100 120
FIG. 2. Fig. 1 reduced to lantern slide size (one-third original chart dimen-
sions). Lettering: height of letters, H-3; width of line, W-2. Lines: curve,
2J/2 points; reference line, ll/% points; grid rulings, */2 point.
(8) The chart should be precise in execution so as to lend an
impression of reliability.
RELATING TO LINE CHARTS
Curves
(9) The curve is the most important element of a chart and
should have the heaviest weight of line6 to distinguish it sharply
from the background.
Feb., 1933]
CHARTS FOR LANTERN SLIDES
145
(10) Ordinarily, not more than three curves should be shown
on the same chart. This limitation does not apply to curves that
are similar in shape and well separated.
(11) If the curve represent a series of observations, the ob-
served points should be shown, provided that by so doing, additional
essential information is given as to the character of the data or as
to the reliability of the curve. Observed points should preferably
be represented by circles or other closed symbols rather than by
\
/
/
\
©
f
HP/.N
WIDT
5
4
3
a
0
<
V
CH POWER TRANSMITTED BY BELTING
M DOUBLE MACHINE-BELT
\
s~
>*
/
\
/
\
V
/
\
/
\
) 2000 4000 6000 800O
VELOCITY OF BELT. FT. PER MIN.
J
FIG. 3. Another illustration of a horizontal chart. Lettering: title height
of letters, H-l; width of line, W-l. Sub-title, scale numbers, scale captions:
height of letters, H-3; width of line, W-2.
crosses. For such symbols, a minimum width of line should be used.
Grid Rulings
(12) Grid rulings should be limited in number to those neces-
sary to guide the eye for an approximate reading.
Closely spaced grid rulings are appropriate for computation charts,
but not for charts prepared merely to show relation.
(13) Grid rulings, including boundaries of the grid area but
146
CHARTS FOR LANTERN SLIDES
[J. S. M. p. E.
excluding reference lines, should have the lightest weight of any
lines on the chart.
(14) Principal lines of reference, such as the zero line, should
be made heavier than other rulings but lighter than the curves.
Unit of
Measurement
Shown
\
Horizontal
Lettering
Where
Possible
Capital
Gothic
Letters
Minimum
Number of
Grid Rulings
HORSE HEAD /
ACROSS GRAIN/
ITH GRAIN—'
0 50 tOO ISO 200
TEMPERATURE OF SPECIMEN, DEC. CENT.
Grid Rulings Break at
Labels and Symbols
Closed Symbols for
Observed Points
Position of
Slide Number
Label
(Thumb Spot)
FIG. 4. Illustration of a vertical chart (size of original 6 X 8l/4 in., including
margins).
(15) Grid rulings should not run through any lettering on the
chart nor through circles representing observed points.
Scales, Scale Captions, and Designations
(16) Scales and scale captions should usually be placed at the
left and at the bottom of the chart. The scale caption for the verti-
Feb., 1933 J
Designation
H-l
CHARTS FOR LANTERN SLIDES
TABLE i
Lettering
Size of Letters
Sample Letters
ABCDE
147
Approx. Height,
Inches
0.175
H-2
ABCDE
0.140
Designation
W-l
ABCDE
Line Width of Letters
Sample Line
0.120
Approx. Width,
Inches
0.025
W-2
0.017
W-2
0.017
See the Appendix for information on height of letters and width of lines for
several commercial lettering templates and pens.
TABLE II
Line Widths
Printer's
Lines Designation
Width,
Inches
0.042
0.035
0.028
0.021
0.014
0.007
0.007
D • A Q H point
148 CHARTS FOR LANTERN SLIDES [j. s. M. p. E.
cal scale should if practicable be arranged in horizontal lines above
the upper end of the scale.
(17) The horizontal (independent variable) scale values should
usually progress from left to right, and the vertical (dependent
variable) scale values from bottom to top.
(18) The scale caption should indicate both the quantity mea-
sured and the unit of measurement.
(19) For arithmetical scales, the scale figures shown on the chart
and the space between grid rulings should preferably correspond to
1, 2, or 5 units of measurement, multiplied or divided by 1, 10, 100, etc.
(20) Scales should be chosen with a view to making full use of the
grid area. When the zero line is a principal standard of reference, it
should appear on the chart if its presence clarifies the meaning of the
chart.
(21). Curves should usually be designated by word-labels placed
horizontally close to the curves, rather than by key letters or num-
bers. When necessary, an arrow can be drawn to connect label and
curve.
NOTES
Note 1. — Attention is called to the possibilities of using negative slides and
colors. "Negative" slides (white lines on black background) are less fatiguing
to the audience and cost less than "positives"; but should be used only in a
thoroughly darkened room. If there be any doubt on this question, it is safer
to use "positives."
Appropriate use of color increases the effectiveness of slides. If there is any
likelihood of publishing the chart, a black and white original should be used
and the coloring done by hand on the slide. A colored original satisfactory
for making a colored slide by direct color photography must be redrawn in
black and white for publication. Colored slides cost more than black and white
ones and the technic is beyond the scope of this brochure.
Note 2. — While most publications have their own standards of line widths for
engineering charts, the committee finds that the following give results that are
representative of good current practice:
(a) Line widths on original chart:
Curves — lx/2 to 2 points (depending on nature and number of curves)
Reference Lines — 1 point.
Grid Rulings — Vz point.
(See Tables I and II for examples of line widths designated by "points.")
(&) Original charts to be reduced to one-half original dimensions for use as
illustrations for publication (and to one-third original dimensions for
use as lantern slides).
Feb., 1933] CHARTS FOR LANTERN SLIDES 149
Note 3. — Although slightly more area is possible with proportions more nearly
square, the Committee feels that those recommended provide a proper compro-
mise between maximum area, pleasing proportions, opportunity for choice
between vertical and horizontal presentation, and use of the same original for a
variety of media.
Note 4. — The recommended size of lettering and width of line for letters are
based on ophthalmological data, actual tests, and an investigation of the condi-
tions under which standard projection equipments are used.
The ratio of the preferred height of letter on the screen to the distance to the
farthest spectator is 1:300 — that is, 1-inch letter for 25-foot distance, 2- inch
letter for 50-foot distance, etc. The recommendations of paragraph 5 give this
ratio for the following typical conditions:
(a) The lens of the projection lantern has a 12-inch focal length.
(b) The farthest spectator is at the same distance from the screen as the
lantern. (Under average conditions, the. lantern is rarely, of necessity,
placed closer to the screen than the farthest spectator.)
For these conditions, the width of image of a 3-inch lantern slide opening is
equal to l/\ the distance from screen to farthest spectator. For the exceptional
case, the following simple calculation gives the preferred size of letter:
(distance, farthest spectator to screen)
Height of letter on slide, in inches = 0.040 X - — —
(distance, lantern to screen)
(focal length of lens, in inches)
~vT
The Committee finds further that the recommended size of lettering is just
legible to a spectator located at lantern distance from the screen, if a lens of
18-inch focal length is used.
The Committee has assembled data indicating that slides made according to
the recommended practice of paragraph 5 are satisfactory in almost all cases.
Note 5. — This is easily done by the use of commercial lettering guides and
pens provided for this purpose. The appended table gives, for reference pur-
poses, the height of letters and width of line for several commercial lettering
templates and lettering pens.
Where experienced technic is available, modification of these recommendations
as to style and size of lettering may be found justified.
In cases where slides must be prepared on short notice, comparable results
may be obtained by using pica size typewriter lettering (10 letters to the inch)
with an original chart size of 5x/4 X 7J/2 inches, reducing the chart to about
40 per cent of its original dimensions. Although this gives the recommended
size of lettering, slides made in this way may be somewhat less legible than
those made with the template lettering suggested, due in part to the lesser black-
ness and sharpness of line for typewriter lettering.
Note 6. — The weight of line for a family of curves may be made slightly lighter,
and for a single curve slightly heavier than the average shown in Fig. 1 (21/2
points). Cf. Figs. 2, 3, and 4.
150
CHARTS FOR LANTERN SLIDES
APPENDIX*
Table of Commercial Lettering Templates and Lettering Pens
Templates
Maker
Wood-Regan Instru-
ment Co.,
New York, N. Y
Keuffel and Esser
Co.,
New York, N. Y.
Nominal
Letter
Code
Height,
Inches
Pt
"Wrico"
VCN-175
0.175
used with
VCN-140
0.140
used with
VCN-120
0.120
used with
"Leroy"
175C
0.175
used with
140C
0.140
used with
120C
0.120
used with
Line
Width,
Code
Inches
"Wrico"
No. 6
0.025
No. 7
0.017
No. 7
0.017
"Leroy"
No. 2
0.024
No. 0
0.017
No. 0
0.017
REFERENCES
"Summary and Report of Joint Committee on Standards for Graphical Pre-
sentation," published by the A. S. M. E. in December, 1915. Out of print.
BRINTON, W. C.: "Graphic Methods for Presenting Facts," Engineering
Magazine Company, New York, N. Y., 1914.
BROWN, T. H.: "Laboratory Handbook of Statistical Methods," McGraw-
Hill Book Company, Inc., New York, 1931.
HASKELL, A. C.: "How to Make and Use Graphic Charts," Codex Book
Company, Norwood, Mass., 1919.
KARSTEN, K. G.: "Charts and Graphs," Prentice-Hall, Inc., New York, 1923.
KiGGLEMAN, J. R., AND FRiSBEE, I. N.: "Business Statistics," McGraw-Hill
Book Company, Inc., New York, 1.932.
* The Appendix is added for information only.
Recommended Practice
It does not form part of the
LIST OF MEMBERS
AALBERG, JOHN O. (M)
126 N. Vista St., Los Angeles, Calif.
ABRIBAT, MARCEL (M)
Kodak Pathe Research Laboratory,
30 Rue des Vignerons, Vincetmes
(Seine), France.
ADAIR, S. E. (M)
Jenkins & Adair, 3333 Belmont
Ave., Chicago, 111.
AKEMANN, WALTER (4)
Falkenried, 16, Berlin-Dahlem, Ger-
many.
ALBIN, F. G. (4)
1030 S. Arapahoe St., Los Angeles,
Calif.
ALDERSON, RODERICK G. (A)
British International Pictures, Ltd.,
Elstree, Herts, England.
ALEXANDER, DON M. (M)
Alexander Film Industries, Inc.,
Colorado Springs, Colo.
ALLER, JOSEPH (If)
P. O. Box 1000, Hollywood, Calif.
ANDERS, HUGO (-4)
Jam Handy Picture Service, 6227
Broadway, Chicago, 111.
ANDRES, LLOYD J. (M)
Automatic Musical Instrument Co.,
1500 Union Ave., S. E., Grand
Rapids, Mich.
ANDREWS, LEROY O. (A)
26 Wedgwood St., Squantum, Mass.
ANTOFILLI, JOHN (M)
Akeley Camera, Inc., 175 Varick St.,
New York, N. Y.
ATKINSON, S. C. (4)
Regina Photo Supply, Ltd., 1924
Rose St., Regina, Sask., Canada.
BADGLEY, F. C. (M)
Canadian Government Motion Pic-
ture Bureau, Ottawa, Ont.,
Canada.
BAIRD, HOLLIS S. (A)
Shortwave & Television Corp., 70
Brookline Ave., Boston, Mass.
BAKER, GEORGE W. (A)
20 McEldowny St., Chicago Heights,
111.
BAKER, JUDD O. (Af)
RCA Victor Co., Camden, N. J.
BAKER, RAY J. (A)
1911 Kalakaua Ave., Honolulu,
Hawaii.
BAKER. W. R. G. (M)
RCA Victor Co., Camden, N. J.
BAKHSHI, M. N. (A)
P. O. Hill, Bagham, Via Jhelum,
Punjab, India.
BALK AM, HERBERT H. (A)
Brooklyn Edison Co., 380 Pearl St.,
Brooklyn, N. Y.
BALL, J. A. (M)
Technicolor Motion Picture Corp.,
823 N. Seward St., Hollywood,
Calif.
BALTIMORE, DAVID M. (A)
Moving Picture Theater Managers
Institute, 315 Washington St.,
Elmira, N. Y.
BAMFORD, WM. B. (4)
614 10th Ave., Belmar, N. J.
BANKS, CHAS. (4)
Regent Theater, Gisborne, New
Zealand.
BARRELL, C. W. (M)
Western Electric Co., 120 W. 41st
St., New York, N. Y.
*(M) Active Member
(.4) Associate Member
151
152
LIST OF MEMBERS
[J. S. M. P. E.
BARROWS, THAD C. (A)
Metropolitan Theater, Boston, Mass.
BARTH, ARTHUR (4)
Carl Zeiss, Inc., 485 Fifth Ave., New
York, N. Y.
BARZEE, G. W. (A)
Caixa Postal 494, Sao Paulo, Brazil.
BASS, CHARLES 04)
Bass Camera Co., 179 W. Madison
St., Chicago, 111.
BATSEL, MAX C. (M)
RCA Victor Co., Camden, N. J.
BAUER, CHARLES W. (M)
57 Shaler Ave., Cliffside, N. J.
BAUER, KARL A. (4)
Carl Zeiss, Inc., 485 Fifth Ave.,
New York, N. Y.
BECKER, ALBERT (A)
National Theater Supply Co., 500
Pearl St., Buffalo, N. Y.
BEERS, NATHAN T. (M)
420 Clinton Ave., Brooklyn, N. Y.
BEETSON, FREDERICK W. (M)
Assoc. of Mot. Pict. Producers, Inc.,
5504 Hollywood Blvd., Holly-
wood, Calif.
BELTZ, WILLIS H. (M)
RCA Victor Co., 153 E. 24th St.,
New York, N. Y.
BENDHEIM. EDMUND McB. (.4)
21-24 Thirty-first St., Astoria, L. I.,
N. Y.
BENNETT, DONALD P. (4)
655 E. 233rd St., New York, N. Y.
BERNDT, ERIC M. (M)
112 E. 73rd Street, New York, N. Y.
BERTHON, RODOLPHE (M)
1 Rue du Chemin de Fer, a Croissy,
France.
BERTIN, HENRI (4)
79 Blvd. Haussmann, Paris, France.
BESNARD, MAURICE (M)
Compagnie Radio Cinema, 79 Blvd.
Haussmann, Paris, VIII, France.
BETHELL, JAMES G. (4)
Kiddle, Margeson, & Hornidge, 511
Fifth Ave., New York, N. Y.
BETTS, WALTER L. (M)
Bell Telephone Laboratories, 463
West St.. New York, N. Y.
BIELICKE, WM. F. (M)
Astro-Gesellschaft m. b. h., Lahnstr.,
30, Berlin-Neukolln, Germany.
BIELICKE, WILLIAM P. (M)
820 N. Martel Ave., Los Angeles,
Calif.
BLAIR, GEORGE A. (M)
Eastman Kodak Co., 343 State St.,
Rochester, N. Y.
BLAKE, E. E. (A)
Kodak, Ltd., 63 Kingsway, London,
W. C. 2, England.
BLANEY, J. M. (M)
51 Sterling Place, Amityville, L. I.,
N. Y.
BLINN. ARTHUR F. (A)
1403 N. Orange Grove, Hollywood,
Calif.
BLIVEN, J. E. (M)
Box 91, New London, Conn.
BOHM, HANS (A)
Prinzregentenstr., 93, Berlin-Wil-
mersdorf, Germany.
BORNMANN, CARL A. (M)
Agfa Ansco Corp., Camera Works,
Johnson City, N. Y.
BOYLEN, JOHN C. (-4)
Ontario Govt. M. P. Bureau, Parlia-
ment Bldgs., Toronto, Ont.,
Canada.
BRADFORD, ARTHUR J. (4)
Jam Handy Picture Service, 2900
E. Grand Blvd., Detroit, Mich.
BRADSHAW, A. E. (4)
1301 Sixth Ave., Tacoma, Wash.
BRADSHAW, DAVID Y. (M)
Fox Hearst Corp., 460 W. 54th St.,
New York, N. Y.
BREITENSTEIN, S. (M)
320 E. 176th St., New York, N. Y.
B REUSING, KURT (M)
Mechanische. Optische Werkstatten,
G. m. b. h., Potsdamerstr., 38,
Berlin, W. 35, Germany.
Feb., 1933]
LIST OF MEMBERS
153
BREWSTER, P. D. (M)
Brewster Color Film Corp., 58 First
St., Newark, N. J.
BRIDGE, WILLARD E. (-4)
1041 N. Formosa St., Hollywood,
Calif.
BROCK, GUSTAV F. O. (A)
528 Riverside Dr., New York, N. Y.
BROWN, FREEMAN LEE (A)
22 Ormond Ave., Oaklyn, N. J.
BROWN, J. CALVIN (M)
704 S. Spring St., Los Angeles, Calif.
BUCKLES, J. O. (A)
1609 W. 40th St., Oklahoma City,
Okla.
BUENSOD, ALFRED G. (A)
Carrier Engineering Corp., Chrysler
Building, New York, N. Y.
BURCHETT, C. W. 04)
Theater Lighting & Equipment Co.,
255 Golden Gate Ave., San Fran-
cisco, Calif.
BUREL, L. H. (A)
5 Rue Leon Coquiet, Paris, XVII,
France.
BURGESS, FRANCIS J. (4)
Camera Dept., Paramount Publix
Corp., 5451 Marathon St., Holly-
wood, Calif.
BURNAP, ROBERT S. (M}
RCA Radiotron Co., 415 S. 5th St.,
Harrison, N. J.
BURNAT, HENRY (4)
70 Rue Lauriston, Paris, France.
BURNETT, J. C. (M}
Burnett-Timken Research Labora-
tory, Alpine, N. J.
BURNS, ROBERT P. (^4)
3034 Leland Ave., Chicago, 111.
BURNS, S. R. (M)
International Projector Corp., 90
Gold St., New York, N. Y.
BUSCH, HERMAN (4)
1306 S. Michigan Ave., Chicago, 111.
BUSCH, LEO N. (A)
Kodak A.-G., Friedrichshagener-
str., 9, Berlin-Copenick, Germany.
BUSSE, FERDINAND (M)
Agfa Ansco Corp., Binghamton,
N. Y.
BUSSELL, ELMER J. (A)
1030 W. 49th St., Los Angeles,
Calif.
BUTTOLPH, LEROY J. (M)
General Electric Vapor Lamp Co.,
Hoboken, N. J.
CABIROL, CHRISTIAN (A)
Pathescope, Ltd., 5 Lisle St., Leices-
ter Sq., London, W. C. 2, England.
CAHILL, FRANK E., JR. (M]
Warner Bros. Theaters, Inc., 321
W. 44th St., New York, N. Y.
CAMERON, JAMES R. (M)
Cameron Publishing Co., Wood-
mont, Conn.
CANADY, DON R. (If)
19570 S. Sagamore Rd., Cleveland,
Ohio.
CANTRELL, W. A. (4)
503 East Prescot Road, Knotty Ash,
Liverpool, England.
CAPSTAFF, JOHN G. (Af)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
CARLTON, JAMES L. (M)
J. L. Carlton Labs., Inc., 90-25 Co-
rona Ave., Elmhurst, L. I., N. Y.
CARPENTER, A. W. (A)
United Research Co., 41-40 Harold
Ave., Long Island City, N. Y.
CARPENTER, ERNEST S. 04)
Escar Motion Picture Service, Inc.,
10008 Carnegie Ave., Cleveland,
Ohio.
CARSON, W. H. (M)
Agfa Ansco Corp., Binghamton,
N. Y.
CARULLA, ROBERT (4)
1254 E. 31st St., Brooklyn, N. Y.
CASS, JOHN L. (M)
RCA Victor Co., Camden, N. J.
CECCARINI, O. O. (M)
Metro-Goldwyn-Mayer Studios, Cul-
ver City, Calif.
154
LIST OF MEMBERS
[J. S. M. P. E.
CHAMBERS, GORDON A. (M)
Eastman Kodak Co., 6706 Santa
Monica Blvd., Hollywood, Calif.
CHANIER, GASTON L. (M)
. Old Short Hills Road, Short Hills, NJ.
CHAPMAN, SHELBY C. (A)
Glendale, Calif.
CHARNEY, FELIX A. (^4)
8827 Woodhaven Blvd., Wood-
haven, L. I., N. Y.
CHEFTEL, ALEXIS M. (A)
22 Rue de Civry, Paris, XVI,
France.
CHILTON, THOMAS (A)
J. Frank Brockliss, Ltd., 58 Great
Marlborough St., London, W. 1,
England.
CHRETIEN, HENRI (A)
23 Rue Preschez, St. Cloud, France.
CIFRE, J. S. (M)
National Theater Supply Co., 211
Columbus Ave., Boston, Mass.
CLARK, CHARLES H. (M)
1147 Hartzell St., Pacific Palisades,
Calif.
CLARK, LAURISTON E. (M)
2327 Glendon Ave., West Los
Angeles, Calif.
CLARK, REX S. (M)
Clark Cine Service, 203 Professional
Bldg., Detroit, Mich.
CLARK, WALTER (M)
Research Laboratories, Eastman
Kodak Co., Rochester, N. Y.
CLAYTON, JOSEPH (M)
94-30 46th Ave., Elmhurst, L. I.,
N. Y.
CLAYTON, ROY S. (4)
Metropolitan Sound Studio, Holly-
wood, Calif.
COHAN, EDWIN K. (A)
Columbia Broadcasting System, 485
Madison Ave., New York, N. Y.
COHEN, JOSEPH H. (M)
Atlantic Gelatin Co., Hill St.,
Woburn, Mass.
COLSON, PARDEE D. (A)
Rabun Theater, Clayton, Ga.
COMSTOCK, THEODORE F. (A)
Pathescope Co. of America, Inc., 33
W. 42nd St., New York, N. Y.
CONTNER, J. BURGI (M}
Blue Seal Sound Devices, Inc., 130
W. 46th St., New York, N. Y.
COOK, ALAN A. (A)
Bausch & Lomb Optical Co., 635
St. Paul St., Rochester, N. Y.
COOK, OTTO W. (M)
Eastman Kodak Co., 343 State
Street, Rochester, N. Y.
COOK, WILLARD B. (M)
Kodascope Libraries, 33 W. 42nd
St., New York, N. Y.
COOLEY, W. D. (A)
RCA Victor Co. of China, Shanghai,
China.
CORRIGAN, JAMES T. (A)
1819 G St., N. W., Washington,
D. C.
COUR, EUGENE J. (If)
Pathe News, 1023 S. Wabash Ave.,
Chicago, 111.
COURCIER, J. L. (A)
J. E. Brulatour, Inc., 6700 Santa
Monica Blvd., Hollywood, Calif.
COWAN, LESTER (M}
Academy of Motion Picture Arts &
Sciences, 7046 Hollywood Blvd.,
Hollywood, Calif.
COWLING. HERFORD TYNES (M)
311 Alexander St., Rochester, N. Y.
COZINE, ARTHUR (A)
877 Sterling Place, Brooklyn, N. Y.
COZZENS, Louis S. (M}
Du Pont Film Mfg. Co., Parlin,
N. J.
CRABTREE, JAMES (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
CRABTREE, JOHN I. (M)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
CRAPP, GEORGE L. (A)
Shirley Court, Stonehurst, Pa.
Feb., 1933]
LIST OF MEMBERS
155
CRENNAN, OLLIE V. (^4)
200 Eastchester Road, New Rochelle,
N. Y.
CRESPINEL, WILLIAM T. (M)
Cinecolor Inc., 201 N. Occidental
Blvd., Hollywood, Calif.
CRIST, RICHARD (A)
5923 Beach Drive, Seattle, Wash.
CULLEN, CEDRIC W. (A)
131 Gladstone Ave., Windsor, Ont.,
Canada.
CULLEN, ROBERT S. (A)
12 Maiden Lane, New York, N. Y.
CUNNINGHAM, ROBERT G. (A)
Agfa Raw Film Corp., 1328 Broad-
way, New York, N. Y.
CUNNINGHAM, THOS. D. (A)
RCA Victor Co., Camden, N. J.
CURLE, CHARLES E. (A)
Box 1614, Station A, Chattanooga,
Tenn.
CURTIS, EDWARD P. (M)
Eastman Kodak Co., 343 State
Street, Rochester, N. Y.
DALOTEL, MAURICE (A)
Material Cinematographique, 111,
113 Rue St. Maur, Paris, XI,
France.
DANA, ALAN S. (A)
Kerite Insulated Wire & Cable Co.,
Seymour, Conn.
DANASHEVSKY, ANATOLE W. (A)
21 Nadeshjeanskaya, Apt. 20, Lenin-
grad, U. S. S. R.
D'ARCY, E. W. U)
Spoor-Ahbe Studios, 1245 Argyle
St., Chicago, 111.
DASH, C. C. (Jlf)
Hertner Electric Co., 12690 Elm-
wood Ave., Cleveland, Ohio.
DAVEE, LAWRENCE W. (M)
153 Westervelt Ave., Tenafly, N. J.
DAVIDGE, LEROY C. (10
Roy Davidge Film Laboratories,
6701 Santa Monica Blvd., Holly-
wood, Calif.
DAVIDSON, L. E. (.4)
775 Main St., Buffalo, N. Y.
DEBRIE, ANDRE (M)
Material Cinematographique, 111,
113 Rue St. Maur, Paris, France.
DE FEO, LUCIANO 04)
Villa Medioevale Torlonia, via Laz-
zaro Spallanzani, Rome, Italy.
DEFFORGE, MARCEL (M)
6 bis, Rue Laure Fiot, Asni&res
(Seine), France.
DE FOREST, LEE (M)
8190 Hollywood Blvd., Hollywood,
Calif.
DE FRENES, JOSEPH (M)
De Frenes Co., 60 N. State St.,
Wilkes-Barre, Pa.
DEGHUEE, CHAS. M. (A)
101 Liberty Ave., Mineola, L. I.,
N. Y.
DE MALLIE, RICHARD B. (A)
Kodak Japan, Ltd., 3-Nishiroku-
chome, Ginza, Tokyo, Japan.
DE Moos, CHARLES (A)
Du Pont Film Mfg. Co., Parlin, N. J.
DEPUE, BURTON W. (M)
Burton Holmes Lectures, Inc., 7510
N. Ashland Ave., Chicago, 111.
DEPUE, O. B. (M}
7512 N. Ashland Ave., Chicago, 111.
DE ROBERTS, RAYMOND (A)
Gevaert Co. of America, Inc., 423
W. 55th St., New York, N. Y.
DESAI, HARIBHAI R. (If)
Surya Film Co., 5 Cunningham Rd.,
Bangalore City, Mysore State,
India.
DE URGOITI, RICARDO M. (4)
Film6fono, S. A., 4 Plaza del Callao,
Madrid, Spain.
DEVRY, H. A. (M)
1111 Center St., Chicago, 111.
DsWiTT, H. N. (A)
36 Toronto St., Toronto, Ont., Can.
DICKINSON, ARTHUR S. (A)
Motion Picture Prod. & Dist. of
America, Inc., 28 W. 44th St., New
York, N. Y.
156
LIST OF MEMBERS
[J. S. M. p. E.
DlDIEE, L. J. J. (4)
Societe Kodak-Pathe, 39 Ave. Mon-
taigne, Paris, France.
DIETERICH, L. M. (M)
2026 Holly Hill Terrace, Hollywood,
Calif.
DOBSON, GEORGE (M)
494 Dwas Line Road, Clifton, N. J.
DODDRELL, E. T. JR. 04)
151 Wainui Road, Kaiti, Gisborne,
New Zealand.
DOIRON, ALPHONSE L. (^4)
Metro - Goldwyn - Mayer Studios,
Culver City, Calif.
DONER, FRANK M. (^4)
Station B, P. O. Box 6, Toledo, Ohio.
DOUGLAS, LEON F. (M}
Menlo Park, Calif.
DOWNES, A. C. (M)
National Carbon Co., Box 400,
Cleveland, Ohio.
DREHER, CARL (M)
RKO Studios, Inc., 780 Gower St.,
Hollywood, Calif.
DUBRAY, JOSEPH A. (M)
Bell & Howell Co., 716 No. La Brea
Ave., Hollywood, Calif.
DUDIAK, FRANK (A)
Fairmont Theater, Fairmont, W. Va.
DUISBERG, WALTHER H. (A)
Patent Research, Inc., 521 Fifth
Ave., New York, N. Y.
DUNNING, CARROLL H. (M)
Dunning Process Co., 932 N. La
Brea Ave., Hollywood, Calif.
DUNNING, DODGE (A)
Dunning Process Co., 932 N. La
Brea Ave., Hollywood, Calif.
DUNNING, ORVILLE M. (A)
Thos. A. Edison, Inc., West Orange,
N.J.
DURHOLZ, OTTO B. (^4)
21 Martin St., Paterson, N. J.
DUTTON, WATSON P. (M)
RCA Victor Co., Camden, N. J.
DWYER, RAYMOND J. (^4)
Eastman Kodak Co., 343 State St.,
Rochester, N. Y.
DYKEMAN, CHESTER L. (A)
Dyke Cinema Products Co., 133-12
228th St., Laurelton, L. L, N. Y.
ECKLER, LEOPOLD (M)
Agfa Ansco Corp., Binghamton,
N. Y.
EDISON, THEODORE M. (A)
Thos. A. Edison, Inc., West Orange,
N.J.
EDOUART, A. F. (A)
Paramount Publix Corp., 5451 Mara-
thon St., Hollywood, Calif.
EDWARDS, GEORGE C. (M)
49 Trafalgar Square, Lynbrook, L. I.,
N. Y.
EGROT, LUCIEN G. (A)
58 Blvd. National, Vincennes, Seine,
France.
ELLISON, MICHAEL (A)
2240 Ogden Ave., Chicago, 111.
ELMS, CHARLES D. (M)
10 Westbury Ave., Staten Island,
N. Y.
ELWELL, CYRIL F. (.4)
197 Queens Gate, London, S. W. 7,
England.
EMSLIE, EMMETT K. (A)
907 W. Hamilton St., Flint, Mich.
ENGL, JOSEF B. (M)
Bismarckstr., 97, Berlin- Charlotten-
burg, Germany.
EPSTEIN, FAB JAN (A)
Wilcza str. 29a/12, Warsaw, Poland.
EVANS, PORTER H. (M)
Warner Bros. Pictures, Inc., 1277
E. 14th St., Brooklyn, N. Y.
EVANS, RALPH M. (A)
De Luxe Laboratories, Inc., 441
W. 55th St., New York, N. Y.
EVANS, RAYMOND (M)
Division of Motion Pictures, U. S.
Dept. of Agriculture, Washington,
D. C.
Feb., 1933]
LIST OF MEMBERS
157
FAITHFULL, GEOFFREY (M)
Archibald Nettlefold Productions,
The Studios, Hurst Grove, Wal-
ton-on-Thames, England.
FALQUET, ALBERT (A)
Kodak, S. P. z. o. o., 5 Place Na-
poleon, Warsaw, Poland.
FARNHAM, R. E. CM)
Engr. Dept., General Electric Co.
Nela Park, Cleveland, Ohio.
FARRAND, CLAIR L. (M)
United Research Corp., 321 W. 44th
St., New York, N. Y.
FAULKNER, TREVOR (A)
117 W. 45th St., New York, N. Y.
FAYE, JAMES J. (A)
Racquet and Tennis Club, 370 Park
Ave., New York, N. Y.
FELSTEAD, CHARLES F. (A)
2010 Sixth Ave., Los Angeles, Calif.
FENIMORE, ROGER W. (M)
Chicago Film Lab., Inc., 1322 Bel-
mont Ave., Chicago, 111.
FINN, JAMES J. (A}
1 W. 47th St., New York, N. Y.
FITZPATRICK, JOSEPH M. S. (A)
Kodak, Ltd., Wealdstone, Middle-
sex, England.
FLANNAGAN, COKE (M)
Electrical Research Products, Inc.,
250 W. 57th St., New York, N. Y.
FLEISCHER, MAX (M)
Fleischer Studios, Inc., 1600 Broad-
way, New York, N. Y.
FLINT, ASHER (.4)
8 Jochum Ave., Larchmont, N. Y.
FLORY, Louis P. 04)
Boyce-Thompson Institute, 1086 N.
Broadway, Yonkers, N. Y.
FLYNN, KIRTLAND (M)
Celluloid Co., 290 Ferry St., Newark,
N. J.
FOOTE, PAUL C. (A)
Bell & Howell Co., 4045 N. Rockwell
St., Chicago, 111.
FORD, MAURICE (^4)
Afritone Productions, Ltd., Braeside,
Herschel Walk, Wynberg, C. P.,
South Africa.
FORD, BERT. (A)
3 Belmont House, Candover St.,
London, W. 1, England.
FOSTER, WARREN D. (M)
Kinatome Patents Corp., 4 Wilsey
Sq., Ridgewood, N. J.
FOWELL, FRANK (M)
The Turning, Kinsbourne Green,
Harpenden, Herts, England.
FRANK, JAMES, JR. (A)
RCA Victor Co., Camden, N. J.
FRANK, KARL G. (M)
75 West St., New York, N. Y.
FRANKLIN, HAROLD B. (.4)
RKO Pictures, Inc., 1560 Broadway,
New York, N. Y.
FRAUNHOFER, HANS VON (M)
United Film Industries, Inc., 420
Madison Ave., New York, N. Y.
FRAYNE, JOHN G. (M)
Electrical Research Products, Inc.,
7046 Hollywood Blvd., Los An-
geles, Calif.
FREEDMAN, ALAN E. (M)
De Luxe Laboratories, Inc., 441 W.
55th St., New York, N. Y.
FREUND, KARL (A)
3093 Lake Hollywood Drive, Holly-
wood, Calif.
FRITTS, EDWIN C. (M)
Eastman Kodak Co., 343 State
Street, Rochester, N. Y.
GAGE, HENRY P. (M)
Corning Glass Works, Corning,
N. Y.
GAGE, OTIS A. (A)
Corning Glass Works, Corning,
N. Y.
GALE, EMANUEL (.4)
c/o Wasserman, 2823 Hubbard St.,
Brooklyn, N. Y.
158
LIST OF MEMBERS
[J. S. M. p. E.
GARLING, W. F. (M)
RCA Photophone, Inc., Film House,
Wardour St., London, England.
GEIB, E. R. (M)
National Carbon Co., Box 400,
Cleveland, Ohio.
GELMAN, J. N. (M)
3439 Jays St., Cincinnati, Ohio.
GENOCK, EDWARD P. (4)
1 Trevanion Rd., West Kensing-
ton, London, W. 14, England.
GERMAN, WILLIAM J. (M)
J. E. Brulatour, Inc., 154 Crescent
St., Long Island City, N. Y.
GERRARD, WILLIAM C. (A)
46 Jayson Ave., Great Neck, L. I.,
N. Y.
GEYER, KARL (-4)
Geyer-Werke, A.-G., Harzerstr. 39/-
42, Berlin, S. O. 36, Germany.
GEYER, WALTER (A)
Treptower Park, 59, Berlin, S. O.
36, Germany.
GIBSON, GEORGE H. (A)
J. E. Brulatour, Inc., 6700 Santa
Monica Blvd., Hollywood, Calif.
GIHBSSON, LEIF (A)
J. L. Nerlien, Ltd., Nedre Slottsgate-
13, Oslo, Norway.
GILMOUR, JOHN G. T. (A)
Visual Instruction Section, General
Electric Co., Schenectady, N. Y.
GLASSER, NAT. (A)
Warner Brothers Theatres, 932 F
St., N. W., Washington, D. C.
GLAUBER, S. (-4)
2062 E. 37th St., Brooklyn, N. Y.
GLEASON, CLARENCE H. (4)
14 N. Hancock St., Lexington,
Mass.
GLENN, CEDRIC L. (A)
1560 Ansel Rd., Cleveland, Ohio.
GLJCKMAN, HARRY (M)
Craft Film Labs., Inc., 136-23 34th
Ave., Flushing, L. L, N. Y.
GLOVER, CHARLES W. (.4)
Abbey House, Westminster, London,
S. W. 1, England.
GLUNT, OMER M. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
GOLDBERG, Jos. H. (M}
Publix Theaters Corp., Paramount
Bldg., New York, N. Y.
GOLDEN, NATHAN D. (A)
Motion Picture Division, U. S. Dept.
of Commerce, Washington, D. C.
GOLDSMITH, ALFRED N. (M)
Radio Corporation of America, 570
Lexington Ave., New York, N. Y.
GOUDY, CARL F. (A)
32-15 N. 17th St., Flushing, L. I..
N.Y.
GRATZER, OTTO (A)
30 Jefferson St., Wellsville, N. Y.
GREEN, NEWTON B. (M)
Engr. Dept. Camera Works, East-
man Kodak Co., Rochester,
N. Y.
GREENE, CHAUNCEY L. (4)
2722 Harriet Ave. S., Minneapolis,
Minn.
GREENE, EDWARD J. (M}
4531 S. 169th St., Flushing, L. L,
N. Y.
GREGORY, CARL Louis (M)
76 Echo Ave., New Rochelle, N. Y.
GRIFFIN, HERBERT (M)
International Projector Corp., 90
Gold St., New York, N. Y.
GRIFFITH, LEIGH M. (A)
6417 W. 6th St., Los Angeles, Calif.
GRIFFITHS, PETER H. (.4)
Western Electric Co., Old Colony
House, South King St., Man-
chester, England.
GRIGNON, LORIN D. (A)
Paramount Publix Corp., 5451 Mara-
thon St., Hollywood, Calif.
GROVER, HARRY G. (A)
Radio Corporation of America, 570
Lexington Ave., New York, N. Y.
GUNN, ALEXANDER H. (4)
6 Sibley Place, Rochester, N. Y.
Feb., 1933]
LIST OF MEMBERS
159
GUPTA, SATISHA C. (A)
Standard Pictures, Ltd., Egerton
Road, Delhi, India.
GUSTIN, RICHARD W. (-4)
Bijou Theater, Bangor, Maine.
HACKEL, JOSEPH 04)
9 Argyle Road, Brooklyn, N. Y.
HAEFELE, NORBERT C. 04)
National Theater Supply Co., 308
N. Gay St., Baltimore, Md.
HALBERTSMA, N. A. 04)
Philips' Glow Lamps Works, Ltd.,
Eindhoven, Holland.
HANDLEY, CHARLES W. (M)
1600 W. 66th St., Los Angeles, Calif.
HANSEN, EDMUND H. (M)
1835 N. Garfield PL, Apt. A., Holly-
wood, Calif.
HARCUS, WILMORE C. (M)
302 N. Oakhurst Drive, Beverly
Hills, Calif.
HARDIN, RUFUS C. (A)
2825 Linden Ave., Knoxville, Tenn.
HARDING, LLOYD E. (M)
307 W. 107th St., New York, N. Y.
HARDY, A. C. (M)
Mass. Institute of Technology, Cam-
bridge, Mass.
HARLEY, JOHN B. (A)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
HARLOW, JOHN B. 04)
Electrical Research Products, Inc.,
250 W. 57th St., New York, N. Y.
HARRINGTON, T. T. (M)
647 Cragmont Ave., Berkeley, Calif.
HA WORTH-BOOTH, MARIE Y. (A)
Debrie Etablissemente, 23 Mortimer
St., London, W. 1, England.
HAYDEN, A. C. (M)
A. C. Hayden Co., Box 496, Brock-
ton, Mass.
HENAULT, GEORGE L. (A)
P. O. Box 69, Brockton, Mass.
HENKEL, JOSEPH F. (4)
11 George St., Brooklyn, N. Y.
HENNESSY, WM. W. (4)
564 S. Goodman St., Rochester,
N. Y.
HERRMAN, HENRY (4)
1747 N. Mayfield Ave., Chicago,
111.
HIATT, AMOS (M)
Pathe News, Inc., 35 West 45th St.,
New York, N. Y.
HICKMAN, KENNETH C. D. (M)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
HIGGINS, ARTHUR E. 04)
Eftee Films, His Majesty's Theater,
Melbourne, Victoria, Australia.
HIGGINS, TASMAN G. (4)
69 Gouett St., Randwick, Sydney,
Australia.
HILLIER, HARRY R. 04)
Mefropolitan Motion Picture Corp.,
1745 E. Grand Blvd., Detroit,
Mich.
HOEFNER, FRED (M )
5319 Santa Monica Blvd., Los
Angeles, Calif.
HOFFMAN, Louis B. (M)
Stuyvesant Woods, Rye, N. Y.
HOGE, JOSEPH F. D. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
HOLLANDER, HARRY 04)
894 Beck St., New York, N. Y.
HOLMAN, ARTHUR J. (M}
57 N. 22nd St., East Orange, N. J.
HOLSLAG, R. C. 04)
Amateur Cinema League, 105 W.
40th St., New York, N. Y.
HOPKINS, JESSE J. 04)
29-41 167th St., Flushing, L. L, N. Y.
HOPPIN, COURTLAND (4)
72 Rue Vaneau, Paris, France.
HORNTDGE, HENRY T. (A)
Kiddle, Margeson & Hornidge, 511
Fifth Ave., New York, N. Y.
HORNSTEIN, JOSEPH C. 04)
Warner Bros. Pictures, Inc., 321 W.
44th St., New York, N. Y.
160
LIST OF MEMBERS
[J. S. M. P. E.
HORSTMAN, CHAS. F. (^4)
Radio-Keith-Orpheum Corp., 1560
Broadway, New York, N. Y.
HORTON, JOSEPH W. (4)
General Radio Co., 30 State St.,
Cambridge, Mass.
HOTCHKISS, FRED H. (^4)
Societe de Material Acoustique, 1
Blvd. Haussman, Paris, France.
HOWELL, A. S. (M)
Bell & Howell Co., 4045 N. Rock-
well St., Chicago, 111.
HOWELL, JOHN F. (M}
Akeley Camera, Inc., 175 Varick St.,
New York, N. Y.
HUBBARD, ROSCOE C. (M)
Consolidated Film Industries, Inc.,
1776 Broadway, New York, N. Y.
HUBBARD, WM. C. (M)
111 W. 5th St., Plainfield/N. J.
HUDSON, GEORGE (A)
Ilford, Ltd., Selo Works, Brentwood,
Essex, England.
HULAN, ARL G . (M)
100 N. Goodman Ave., Kerens,
Texas.
HUMPHREY, GLENN H. (A)
Adcraft Film Service, 1312 Oswego
St., Utica, N. Y.
HUNT, FRANKLIN L. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
HUSE, EMERY (M)
Eastman Kodak Co., 6706 Santa
Monica Blvd., Hollywood, Calif.
HYNDMAN, DONALD E. (M}
Eastman Kodak Co., 350 Madison
Ave., New York, N. Y.
INGMAN, THOMAS A. (A)
1835V2 Grace St., Los Angeles, Calif.
IRBY, FRANKLIN S. (A)
400 E. 58th St., New York, N. Y.
IVER, ROBERT W. (4)
Shea-Publix Theater, Bradford, Pa.
IVES, F. E. (Honorary)
1753 N. 15th St., Philadelphia, Pa.
IVINS, CLINTON F. (4)
Pathescope Co. of America, Inc.,
33 W. 42nd St., New York, N. Y.
JACHONTOW, EUGENE G. (A)
The Optical Institute, Birjevaya
Linia 12, Leningrad, U. S. S. R.
JAMES, F. E. (M)
General Electric Co., 5201 Santa Fe
Ave., Los Angeles, Calif.
JAMIESON, HUGH V. (A}
2212 Line Oak St., Dallas, Texas.
JARRETT, GEORGE J. (A)
Metropolitan Motion Picture Co.,
1745 E. Grand Blvd., Detroit,
Mich.
JAY, RONALD L. (4)
Jay's Screen Service, 23 Nithsdale
Rd., Glasgow, S. 1, Scotland.
JEFFERY, FREDERICK A. (A)
9 Giles St., Toorak, Adelaide, South
Australia.
JENKINS, C. FRANCIS (Honorary)
5502 16th St., Washington, D. C.
JENKINS, J. ELLIOTT (M)
Jenkins & Adair, Inc., 3333 Belmont
Ave., Chicago, 111.
JENSEN, GEORGE K. (M)
12a, Putney Hill, London, S. W. 15,
England.
JOACHIM, HERMANN E. A. (M)
Zeiss-Ikon A.-G., Schandauerstr., 76,
Dresden a 21, Germany.
JOHN, WESLEY E. (A)
National Bank Bldg., Johannesburg,
South Africa.
JONES, JOHN G. (M)
Eastman Kodak Co., Kodak Park,
Rochester, N. Y.
JONES, JOHN M., JR. (A)
629 Tremont Ave., Charlotte, N. C.
JONES, L. A. (M)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
JOY, JOHN M. (M)
12 Fairview Ave., Yonkers, N. Y.
Feb., 1933]
LIST OF MEMBERS
161
KALMUS, HERBERT T. (M)
Technicolor Motion Picture Corp.,
823 N. Seward St., Hollywood, Cal.
KAPLAN, LEW (A)
Motion Picture Service, U. S. Army,
Quarry Heights, Panama Canal
Zone.
KATZ, LAWRENCE J. (4)
P. O. Box 929, Harrisburg, Pa.
KEITH, CLYDE R. (A)
Western Electric Co., Ltd., Coles
Green Road, London, N. W. 2,
England,
KELLEY, WM. V. D. (M)
2228 Holly Drive, Hollywood, Calif.
KELLOGG, EDWARD W. (^4)
RCA Victor Co., Camden, N. J.
KENDE, GEORGE (M)
1312 Hudson Rd., West Englewood,
N.J.
KERSHAW, CECIL (M)
A. Kershaw & Son, 200 Harehills
Lane, Leeds, England.
KEUFFEL, CARL W. (4)
Keuffel & Esser Co., 3rd & Adams
Sts., Hoboken, N. J.
KlENNINGER, JOHN F. (A)
Technicolor Motion Picture Corp.,
1016 N. Cole Ave., Hollywood,
Calif.
KlMBERLEY, PAUL (A)
National Screen Service, Ltd., 25
Denmark St., London, W. C. 2,
England.
KING, FRANK (M)
36 Crestwood Ave., Buffalo, N. Y.
KLEERUP, BERTEL J. (A)
Society for Visual Education, 327
LaSalle St., Chicago, 111.
KLENKE, JOHN, JR. (M)
RCA Victor Co., Hollywood, Calif.
KNOX, HARRY G. (M}
Electrical Research Products, Inc.,
250 W. 57th St., New York,
N.Y.
KRAEMER, GERARD I. (M}
16 Rue de Chateaudun, Asnieres
(Seine), France.
KRANZ.FREDW. (A}
Magnavox Co., Ltd., Fort Wayne,
Indiana. »
KRASNA-KRAUS, ANDOR (.4)
Friedrichstr., 46, Berlin, S. W. 68,
Germany.
KROESEN, J. C. (M}
406 Belleville Ave., Belleville, N. J.
KRUGERS, GEO. E. A. (M}
Krugers Film Corp., Bandoeng,
Java, D. E. I.
KUHN, JOHN J. (M}
Bell Telephone Laboratories, 463
West St., New York, N. Y.
KUMM, ARTHUR W (A}
5412 Virginia Ave., Hollywood, Calif.
KUNZMANN, W. C. (M}
National Carbon Co., P. O. Box
400, Cleveland, Ohio.
KURLANDER, J. H. (M)
Westinghouse Lamp Co., Bloomfield,
N.J.
LA CHAPELLE, Louis (^4)
Consolidated Amusement Co., P. O.
Box 2425, Honolulu, Hawaii.
LAIR, C. (M)
Kodak-Pathe, 30 Rue des Vignerons,
Vincennes (Seine), France.
LAMB, ELGIE E. (M)
Bell & Howell Co., Ltd., 320 Regent
St., London, W. 1, England.
LAMBERT, KENNETH B. (M)
Metro - Goldwyn - Mayer Studios,
Culver City, Calif.
LANE, A. LINDSLEY (M)
3832V2 Westwood Blvd., Culver
City, Calif.
LANE, GEORGE (M)
Audio-Cinema, Inc., 2826 Decatur
Ave., New York, N. Y.
LANGFORD, LEROY P. (M)
12505 Edgewater Drive, Lakewood,
Ohio.
LANSING, DUDLEY W. (A)
RCA Victor Co., Camden, N. J.
162
LIST OF MEMBERS
[J. S. M. P. E.
LA PORTE, NORBERT M. (M)
Paramount Publix Corp., 1501
Broadway, New York, N. Y.
LARUE, MERVIN W. (A )
6157 N. Artesian Ave., Chicago, 111.
LASKY, JESSE L. (A)
Paramount Publix Corp., 1501
Broadway, New York, N. Y.
LAUSTE, E. A. (Honorary)
12 Howard St., Bloomfield, N. J.
LAWLEY, HENRY V. (M)
Lawley Apparatus Co., Ltd., 26
Church St., Charing X Road,
London, W. 1, England.
LEA, WM. DE LANE (A)
283 Promenade des Anglais, Nice,
Alpes Maritimes, France.
LEGENDRE, MORRIS (M)
Royal Zenith Sound Projectors, Inc.,
33 W. 60th St., New York, N. Y.
LEISHMAN, E. D. (.4)
Universal Film Exchanges, Inc., 730
Fifth Ave., New York, N. Y.
LESHING, MICHAEL S. (.4)
Fox Films, Inc., 1401 Northwestern
Ave., Los Angeles, Calif.
LEVENTHAL, J. F. (M)
175 Varick St., New York, N. Y.
LEWIS, WILLIAM W. (4)
6019 Eileen St., Los Angeles, Calif.
LICHTE, H. (M)
Boraweg 3, Berlin-Lankwitz, Ger-
many.
LIDDLE, ALEXANDER J. (^4)
S. Guiterman & Co., Ltd., 36 Alder-
manbury, London, E. C. 2, Eng-
land.
LINS, PERCY A. (A)
Herbert & Huesgen Co., 18 E. 42nd
St., New York, N. Y.
LINSLEY, DOUGLAS F. (4)
The Replitura Corp., Melrose Ave.,
Stamford, Conn.
LITTLE, W. F. (M)
Electrical Testing Lab., 80th St. &
East End Ave., New York,
N. Y.
LONAS, FRANK E. (A)
135 William St., New York, N. Y.
LOOTENS, CHARLES L. (M}
14 Caryl Ave., Yonkers, N. Y.
LUCAS, GEORGE S. C. (A)
British - Thomson - Houston Co.,
Ltd., Rugby, England.
LUHAR, CHIMANLAL M. (M)
Mehta-Luhar Productions, 167 Main
Road, Dadar, Bombay, 14, India.
LUKE, ERNEST (M)
Kenton House, Upper Shirley Rd.,
Croydon, Surrey, England.
LUKES, STANLEY A. 04)
6145 Glenwood Ave., Chicago, 111.
LUMIERE, Louis (Honorary)
156 Blvd. Bineau a Neuilly, Paris,
France.
LUMMERZHEIM, HERMANN J. (.4)
I. G. Farbenindustrie Aktiengesell-
schaft, Berlin, S. O. 36, Germany.
LUNDAHL, TORE (.4)
4404 Sixth Ave., Brooklyn, N. Y.
MAAS, ARTHUR R. (^4)
A. R. Maas Chemical Co., 308 E.
Eighth St., Los Angeles, Calif.
MACILVAIN, KARL H. (M)
3056 7th St., Jackson Heights, L. I.,
N. Y.
MACKENZIE, DONALD (M)
Electrical Research Products, Inc.,
7046 Hollywood Blvd., Los
Angeles, Calif.
MACKLER, A. I. (M)
Film Renovating Co. of America,
Inc., 630 Ninth Ave., New York,
N. Y.
MACLEOD, J. S. (M)
Metro - Goldwyn - Mayer Pictures,
1540 Broadway, New York, N. Y.
MACNAIR, WALTER A. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
MAIRE, HENRY J. (A)
5640 Kingsessing Ave., Philadelphia,
Pa.
Feb., 1933]
LIST OF MEMBERS
163
MALKAMES, DON (M)
Malkames Educational Film Co., 705
W. Diamond Ave., Hazleton, Pa.
MANCHEE, ALLEYNE W. (M)
91 Prospect St., East Orange, N. J.
MANHEIMER, J. R. (M)
E. J. Electrical Installation Co.,
227 E. 45th St., New York, N. Y.
MARCUS. G. KEVA (A)
1923 81st St., Brooklyn, N. Y.
MARESCHAL, GEORGES (4)
168 Rue de Belleville, Paris, XX,
France.
MARETTE, JACQUES (M)
Pathe Cinema, 8 Rue Leconte de
Lisle, Paris, France.
MARSH, HENRY N. (A)
Technical Division, Hercules Pow-
der Co., Wilmington, Del.
MATHOT, JACQUES A. (A)
Eclair Tirage, 34 a 42 Av. d'Enghein,
Epinay sur Seine, France.
MATLACK, CLAUDE C. (A)
327 23rd St., Miami Beach, Fla.
MATTHEWS, GLENN E. (M)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
MAY, R. P. (4)
Haddonfield Manor Apts., Haddon-
field, N. J.
MCAULEY, J. E. (M)
McAuley Mfg. Co. 552 W. Adams
St., Chicago, 111.
MCBURNEY, J. WALTON (A)
Western Electric Co. (N. Z.), Ltd.,
Box 605, G. P. O., Wellington,
New Zealand.
McCANN, FRANCIS D. (A)
Westinghouse Elec. & Mfg. Co.,
150 Broadway, New York, N. Y.
MCCLINTOCK, NORMAN (4)
916 St. James St., Pittsburgh, Pa.
McCROSKEY, H. E. (4)
2203 Broadview Terrace, Holly-
wood, Calif.
McCULLOUGH, R. H. (M}
8408 Blackburn Ave., Los Angeles,
Calif.
MCDOWELL, JOHN B. (A)
Agfa, Ltd., Vintry House, Iveen St.
Place, London E. C. 4, England.
McGiNNis, F. J. (A)
Box 2387, Palm Beach, Fla.
MCGLINNEN, EARL J. (A)
Fox Theater, 2211 Woodward Ave.,
Detroit, Mich.
McGuiRE, PERCIVAL A. (M)
International Projector Corp., 90
Gold St., New York, N. Y.
MCMASTER, DONALD (M)
Kodak Park Works, Eastman Kodak
Co., Rochester, N. V".
MCMATH, R. R. (M)
Motors Metal Mfg. Co., 5936 Mil-
ford Ave., Detroit, Mich.
McNABB, J. H. (M)
Bell & Howell Co., 1801 Larchmont
Ave., Chicago, 111.
MCNAMARA, D. THOMAS (A)
7 Baker Ave., East Lexington, Mass.
McNicoL, DONALD (M)
Projection Engineering, 19 E. 47th
St., New York, N. Y.
McRAE, DONALD (4)
99 Melrose St., Melrose, Mass.
MECHAU, EMIL (A)
Albrechtstr., 60A, Berlin-Sudende,
Germany.
MEES, C. E. K. (M)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
MEHTA, HARSHADRAI S. (M}
Mehta-Luhar Productions, 167 Main
Rd., Dadar, Bombay, 14, India.
MENEFEE, HARRY R. (M}
14 Brookside Circle, Bronxville,
N. Y.
MESSTER, OSKAR (M)
Parkstr., 56/58, Berlin-Dahlem, Ger-
many.
METZGER, MAURICE 04)
Associated Screen News, Ltd., Wes-
tern Ave. & Delcarie Blvd., Mon-
treal, Que., Canada.
164
LIST OF MEMBERS
[J. S. M. p. E.
MEYER, HERBERT (M)
Agfa Ansco Corp., 6370 Santa
Monica Blvd., Hollywood, Calif.
MIEHLING, RUDOLPH (M)
1788 Amsterdam Ave., New York,
N. Y.
MIKETTA, CASIMIR A. (M)
Lyon & Lyon, National City Bank
Bldg., Los Angeles, Calif.
MILLER, ARTHUR W. (A)
47 Westfield Ave., East Roselle
Park. N. J.
MILLER, JAMES A. (A)
c/o N. V. Philips Co., Eindhoven,
Holland.
MILLER, ROBERT A. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
MILLER, WESLEY C. (A)
Metro-Goldwyn-Mayer Studios, Cul-
ver City, Calif.
MISTRY, D. L. (M)
24 Nepean Road, Malabar Hill,
Bombay, 6, India.
MISTRY, M. L. (M)
24 Nepean Road, Malabar Hill,
Bombay, 6, India.
MITCHELL, GEORGE A. (M)
Mitchell Camera Corp., 665 N.
Robertson Blvd., W. Hollywood,
Calif.
MITCHELL, R. FAWN (M)
Bell & Howell Co., 1801 Larchmont
Ave., Chicago, 111.
MOLE, P. (M)
Mole-Richardson, Inc., 941 N. Syca-
more Ave., Hollywood, Calif.
MORENO, R. M. (A)
Du Pont Film Mfg. Corp., Parlin,
N.J
MORGAN, KENNETH F. (M)
Electrical Research Products, Inc.,
7046 Hollywood Blvd., Los
Angeles, Calif.
MORRIS, LLOYD P. (^4)
2620 S. Washington St., Marion,
Ind.
MORTON, H. S. (M)
5650 Grand River Blvd., Grand
River, Mich.
MORTON, TIBOR (A)
Kodak, Ltd., Postafiok 146, Buda-
pest IV, Hungary.
MORTON, WM. M. (A)
R. F. D. No. 7, Knoxville, Tenn.
MOYSE, HOLLIS W. (If)
Smith & Aller, Ltd., 6656 Santa
Monica Blvd., Hollywood, Calif.
MUELLER, WILLIAM A. (M)
1718 N. Sierra Bonita, Hollywood,
Calif.
MULLER, JOHN P. (A)
7825 Hampson St., New Orleans, La.
MURPHY, GEORGE D. (A)
3148 O St., N. W., Washington, D. C.
MURRAY, A. P. (A)
14 Chilton Road, West Roxbury,
Mass.
NADELL, AARON (M)
Publix Theaters Corp., Paramount
Bldg., New York, N. Y.
NAGASE, TOKUTARO (M)
D. Nagase & Co., Ltd., Itachibori-
Minamidori-Nishiku, Osaka,
Japan.
NELSON, OTTO (M)
National Cash Register Co., Dayton,
Ohio.
NEU, GEORGE H. (A)
Neumade Products Corp., 654 Michi-
gan Ave., Buffalo, N. Y.
NEU, OSCAR F. (A)
Neumade Products Corp., 442 W.
42nd St., New York, N. Y.
NICHOLSON, ROBERT F. (M)
Phi Gamma Delta Club, 106 W. 56th
St., New York, N. Y.
NICKOLAUS, JOHN M. (M)
Metro - Goldwyn - Mayer Studios,
Culver City, Calif.
NIEPMANN, CARL H. (A)
Kandem Electrical, Ltd., 711 Ful-
ham Road, London, S. W. 6, Eng-
land.
Feb., 1933]
LIST OF MEMBERS
165
NIXON, IVAN L. (M)
Bausch & Lomb Optical Co.,
Rochester, N. Y.
NORDEN, KONRAD (M)
AllgemeineElektricitats-Gesellschaft,
Friedrich Karl-Ufer 2/4, Berlin,
N. W. 40, Germany.
NORLING, J. A. (M)
Loucks & Norling, 245 W. 55th St.,
New York, N. Y.
NORRISH, B. E .(M)
Associated Screen News of Canada,
Ltd., Western Ave. & Delcarie
Blvd., Montreal, Que., Canada.
OAKLEY, NORMAN F. (A)
Du Pont Film Mfg. Co., Parlin, N. J.
O'BoLGER, ROBERT E. (A)
Eastman Kodak Co., 24 Yuen Ming
Yuen Road, Shanghai, China.
O'KEEFE, GEORGE A. (A)
Warner Bros. Pictures, Inc., 1277
E. 14th St., Brooklyn. N. Y.
OLSON, W. JAMES (A)
National Theater Supply Co., 2310
Cass Ave., Detroit, Mich.
ORAM, EDWIN (A)
"Poole," Shakespeare Rd., Mill Hill,
London, N. W. 7, England.
OSAWA, YOSHIO (A)
J. Osawa & Co., Ltd., Sanjo Ko-
bashi, Kyoto, Japan.
OSBORNE, A. W. (4)
"Hilton" North Drive, Ruislip,
Middlesex, England.
OSTER, E. (A)
5070 Woodley Ave., Van Nuys,
Calif.
OTIS, RUSSELL M. (A)
2089 E. Mountain St., Pasadena,
Calif.
OTT, HARRY G. (M)
Spencer Lens Co., 19 Doat St.,
Buffalo, N. Y.
OWENS, FREEMAN H. (4)
2647 Broadway, New York, N. Y.
PACENT, Louis G. (M)
Pacent Reproducer Corp., 91
Seventh Ave., New York, N. Y.
PAGE, Louis I. (A)
RKO Studios, Inc., 780 Gower St.,
Hollywood, Calif.
PALMER, M. W. (M)
Motion Picture Lighting Co., 34-12
Graham Ave., Long Island City,
N. Y.
PARISH, HAYWARD C. (4)
Berk House, 76 William St., Sydney,
N. S. W., Australia.
PARKER, OLIVER B. (M)
Pacent Electric Co., 91 Seventh Ave.,
New York, N. Y.
PARKINS, C. FRANCIS (A)
Studio Film Laboratories, Ltd., 80
Wardour St., London, England.
PARSHLEY, CHARLES W. (A)
University Theater, Cambridge,
Mass.
PATEL, MANEKLAL BHOGILAL (A)
Krishna & Gujrat Studios, 162 Dadar
Rd., Dadar, Bombay, India.
PATTON, GEORGE E. (M)
Ontario Govt. M. P. Bureau, Parlia-
ment Bldgs., Toronto, Ont., Can.
PECK, W. H. (A)
5 Forest Lane, Scarsdale, N. Y.
PETERSON, F. W. (M)
I. G. Farbenindustrie Aktiengesell-
schaft, Kinotechnische Abteilung,
Berlin, S. O. 36, Germany.
PETTENGILL, GEORGE W., JR. (4)
Motion Picture Service Co., 735
Arlington Ave., N. St. Petersburg,
Fla.
PEYTON, JOHN T. (A)
1240 N. Bath Ave., Oklahoma City,
Okla.
PHELPS, L. G. (M)
Phelps-Films, Inc., 126 Meadow St.,
New Haven, Conn.
PHILLIMORE, C. E. (4)
707 Home Ave., Oak Park, 111.
PHILLIPS, JOSEPH H., JR. (A)
1455 Gordon St., Hollywood, Calif.
166
LIST OF MEMBERS
[J. S. M. P. E.
PIERCE, ROBT. H. (^4)
4538 Denny Ave.f N. Hollywood,
Calif.
PIERSON, ARTHUR E. (A)
513 N. Lucerne Blvd., Hollywood,
Calif.
PlROVANO, LOUIS (-4)
61 Pleasant St., Brookline, Mass.
PLANSKOY, LEONTI (M}
142 Camden Road, London, N. W. 1,
England.
POMEROY, ROY J. (M}
1626 N. Crescent Heights, Holly-
wood, Calif.
POPOVICI, GEO. G. (M)
2975 Marion Ave., Bronx, N. Y.
PORTER, C. D. (4)
Publix Theaters Corp., 57 Ellis St.,
N. E., Atlanta, Ga.
PORTER, LAWRENCE C. (M)
Engr. Dept., General Electric Co.,
Nela Park, Cleveland, Ohio.
POTE, ALFRED J. 04)
270 Chestnut St., Chelsea, Mass.
PRESIDENT, THE (Honorary)
Die Deutsche Kinotechnische Gesell-
schaft, Berlinerstr., 172, Berlin-
Charlottenburg, Germany.
PRESIDENT, THE (Honorary)
Royal Photographic Society, 35
Russell Square, London, W. C. 1.
England.
PRESIDENT, THE (Honorary)
Societe Francaise de Photographic,
51 Rue de Clichy, Paris, France.
PRICE, ARNOLD F. (Af)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
Pu, MAUNG NYI (.4)
Burmese Favourite Co., 51 Sule
Pagoda Road, Rangoon, Burma,
India.
QUTNLAN, WALTER (M)
Fox Film Corp., 1401 Northwestern
Ave., Hollywood, Calif.
RABINOWITZ, DAVID J. (A)
M. Rabinowitz & Sons, Inc., 1373
Sixth Ave., New York, N. Y.
RACKETT, GERALD F. (M}
Technicolor Motion Picture Corp.,
823 N. Seward St., Hollywood,
Calif.
RAMSAYE, TERRY (M}
Motion Picture Herald, 1790 Broad-
way, New York, N. Y.
RANIERI, LUIGI (M)
Geo. Washington Hotel, Lexington
Ave. and 23rd St., New York,
N. Y.
RASMUSSEN, ROBT. T. (A)
458 Archer St., Freeport, L. I., N. Y.
RAVEN, A. L. (M)
Raven Screen Corp., 147 E. 24th St.,
New York, N. Y.
RAY, REID H. (M)
Ray-Bell Films, Inc., 817 University
Ave., St. Paul, Minn.
RAYTON, WILLIAM B. (M)
Bausch & Lomb Optical Co.,
Rochester, N. Y.
READ, EARL A. (-4)
1125 Cleveland Ave., N. W., Canton,
Ohio.
REDFORD, CHAS. F. (A)
The Unicorn Hotel, Altringham,
Cheshire, England.
REDPATH, WM. (M)
156 King St., W. Toronto, Ont., Can.
REEB, OTTO G. L. (A)
Rotherstr., 20-23, Berlin O. 17, Ger-
many.
REEVES, ARTHUR (.4)
Hollywood Motion Picture Equip-
ment Co., Ltd., 6416 Selma Ave.,
Hollywood, Calif.
REIFSTECK, CARL N. (A}
RCA Victor Co., Camden, N. J.
REISMAN, P. H. (M)
362 Pelham Rd., New Rochelle,
N. Y.
RENIER, ALBERT H. (A)
Renier Mfg. Co., 2216 State St.,
Milwaukee, Wis.
Feb., 1933]
LIST OF MEMBERS
167
RENWICK, F. F. (4)
Ilford, Ltd., Ilford, Essex, England.
REPP, WILLIAM H. (4)
Projection Optics Co., 330 Lyell
Ave., Rochester, N. Y.
RICHARD, A. P, (A)
97 Rue Lemercier, Paris, XVII,
France.
RICHARDSON, E. C. (M)
Mole-Richardson, Inc., 941 N. Syca-
more Ave., Hollywood, Calif.
RICHARDSON, FRANK H. (M)
3 Tudor Lane, Scarsdale, N. Y.
RICKER, MAURICE (.4)
39-41 58th St., Woodside, L. I., N. Y.
RICKS, HUBERT M. (.4)
Weston Electrical Instrument Corp.,
614 Frelinghuysen Ave., Newark,
N.J.
RIDER, JOHN F. (M)
1440 Broadway, New York, N. Y.
RINALDY, E. S. (A)
Chester, N. J.
RIPLEY, PAUL L. (4)
Warner Bros. Pictures, Inc., 1277
E. 14th St., New York, N. Y
ROGALLI, N. J. (A)
2753 Cruger Ave., Bronx, N. Y.
ROGERS, JAMES E. (A)
"Cluny," Deacons Hill Road, Els-
tree, Herts, England.
ROHDE, GEORGE (A)
Bausch & Lomb Optical Co., 1401
S. Hope St., Los Angeles, Calif.
ROLAND, EDWARD C. (A)
Ilex Optical Co., 726 Portland Ave.,
Rochester, N. Y.
ROSEMAN, ISIDORE (A)
Kodak A.-G., Markgrafenstr., 7-6,
Berlin, Germany.
ROSENBERGER, HEINZ (A)
Rockefeller Institute, 66th St. &
York Ave., New York, N. Y.
ROSENSWEIG, MORRIS (A)
H. E. R. Laboratories, Inc., 457
W. 46th St., New York,
N. Y.
ROSENTHAL, ALFRED (A)
Zimmerstr., 35, Berlin, S. W. 68, Ger-
many.
Ross, CHARLES (A)
Motion Picture Service Co., 318
W. 48th St., New York, N. Y.
Ross, ERNEST (M)
United Research Corp., 41-39 38th
St., Long Island City, N. Y.
Ross, O. A. (M)
198 Broadway, Room 903, New
York, N. Y.
ROTHENBERG, MAURICE (A)
Globe Theater, Boston, Mass.
ROUSE, J. J. (A)
Kodak Australasia Ptg., Ltd., 379
George St., Sydney, N. S. W.,
Australia.
ROWSON, SIMON (M)
76 Wardour St., London, W. 1,
England.
RUBIN, HARRY (M)
Paramount Publix Corp., Paramount
Bldg., New York, N. Y.
RUDOLPH, WILLIAM F. (A)
Paramount Publix Corp., 5451 Mara-
thon St., Hollywood, Calif.
RUOT, MARCEL (M}
Kodak, Ltd., Kingsway, London,
E. C. 2, England.
RUSSELL, WESLEY F. (M)
Hall & Connolly, Inc., 24 Van Dam
St., New York, N. Y.
RYAN, HARRY (A)
7937 S. Wood St., Chicago, 111.
RYDER, LORIN L. (A)
Paramount Publix Corp., 5451 Mara-
thon St., Hollywood, Calif.
SABINE, PAUL E. (A)
Riverbank Laboratories, Geneva, 111.
SAMUELS, IRVING (A)
Automatic Devices Co., 737 Hamil-
ton St., Allentown, Pa.
SANDVIK, OTTO (A)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
168
LIST OF MEMBERS
[J. S. M. P. E.
SANIAL, ARTHUR J. (M)
140-31 58th Road, Flushing, L. I.,
N. Y.
SANTEE, HOWARD B. (M)
Electrical Research Products, Inc.,
250 W. 57th St., New York, N. Y.
SCHAEFFER, JOHN M. (-4)
1003 Dobson St., Evanston, 111.
SCHELDORF, MARVEL W. (A)
429 Maple Ave., Westmont, N. J.
SCHICK, MARTIN C. (A)
401 W. Washington Blvd., Fort
Wayne, Indiana.
SCHLANGER, BEN (A)
101 Park Ave., New York, N. Y.
SCHMID, FRED (M)
C. P. Goerz American Optical Co.,
317 E. 34th St., New York,
N. Y.
SCHMIDT, WILLY A. (M)
Agfa Ansco Corp., Binghamton,
N. Y.
SCHMITZ, ERNEST C. (-4)
Kodak Co., 39 Ave. Montaigne,
Paris, France.
SCHROTT, PAUL R. VON (4)
Getreidemarkt, 9, Vienna, IV, Aus-
tria.
SCHWARTZ, R. PLATO (M)
School of Medicine, University of
Rochester, Crittenden Blvd.,
Rochester, N. Y.
SCHWARZ, G. ALFRED (A)
Columbus Industrial Film Co., 150
S. Third St., Columbus, Ohio.
SCHWENGELER, CHARLES E. (A)
34-14 Parsons Blvd., Flushing,
L. I., N. Y.
SCRIVEN, EDWARD O. (AT)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
SEASE, VIRGIL B. (M)
Du Pont Film Mfg. Co., Parlin, N. J.
SERRURIER, IWAN (M}
Moviola Co., 1451 Gordon St.,
Hollywood, Calif.
SHAFER, LAWRENCE J. (A)
Rialto Theater, West 25th St. &
Bridge Ave., Cleveland, Ohio.
SHALKHAUSER, E. G. (A)
147 Cooper Ave., Peoria, 111.
SHAMRAY, P. L. (M)
Smith & Aller, Inc., 6656 Santa
Monica Blvd., Hollywood, Calif.
SHAPIRO, A. (M)
Universal Stamping & Mfg. Co.,
2839 Northwestern Ave., Chicago,
111.
SHEA, TIMOTHY E. (M}
Bell Telephone Laboratories, 463
West St., New York, N. Y.
SHEPPARD, SAMUEL E. (If)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
SHERIDAN, P. T. (A)
Electrical Research Products, Inc.,
250 W. 57th St., New York, N. Y.
SHIMEK, JOHN A. (.4)
2207 Byron St., Chicago, 111.
SHIRAS, ANNE (.4)
841 Ellsworth Ave., Pittsburgh, Pa.
SHOTWELL, H. H. (A)
32 N. Worth St., Elgin, 111.
SHULTZ, E. PAT (A)
1016 N. Sycamore Ave., Hollywood,
Calif
SILENT, HAROLD C. (M)
Electrical Research Products, Inc.,
7046 Hollywood Blvd., Los
Angeles, Calif.
SKITTRELL, J. Y. (10
Olympic Kinematograph Labora-
tories, School Road, London, W.
10, England.
SLOAN, JAMES B. (4)
4, The Avenue, Bedford Park,
London, W. 4, England.
SMACK, JOHN C. (4)
5. S. White Dental Mfg. Co., 152
W. 42nd St., New York, N. Y.
SMITH, J. E. (M)
National Radio Institute, 16th &
U Sts., N. W., Washington, D. C.
Feb., 1933]
LIST OF MEMBERS
169
SMITH, J. W. (A)
23 Purley Ave., Cricklewood, Lon-
don, N. W. 2, England.
SOPER, WALTER E. (A)
P. O. Box 245, Ottawa, Ont., Canada.
SPAHR, ORAL F. (M)
4431 W. Lake St., Chicago, 111.
SPENCE, JOHN. L., JR. (M)
Akeley Camera, Inc., 175 Varick St.,
New York, N. Y.
SPONABLE, EARL I. (M)
277 Park Ave., New York, N. Y.
SPRAY, JOSEPH H. (M)
Warner Bros. Pictures, Inc., 1277 E.
14th St., Brooklyn, N. Y.
STAFFORD, J. W. (A)
l237l/2 N. Ogden Drive, Hollywood,
Calif.
STAMBAUGH, REX V. (M)
P. O. Box 418, Cleveland, Ohio.
STECHBART, BRUNO E. (M)
Bell & Howell Co., 1801 Larchmont
Ave., Chicago, 111.
STEDEROTH, FRED F. (4)
41 Watsessing Ave., Bloomfield,
N.J.
STEELE, LAWRENCE L. (A)
S. M. Chemical Co., Inc., 514 W.
57th St., New York, N. Y.
STEWART, GEO. E. (M)
40 Hillside Ave., Rockville Center,
L. I., N. Y.
STOLLER, H. M. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
STONE, CARRINGTON H. (4)
Jenkins & Adair, Inc., 3333 Bel-
mont Ave., Chicago, 111.
STRENGE, F. WALTER (M)
4549 193rd St., Flushing, L. I., N. Y.
STRICKLER, J. F. (4)
Jam Handy Picture Corp., 2900
E. Grand Blvd., Detroit, Mich.
STRONG, HARRY H. (A}
Strong Electric Co., 2501 LaGrange
St., Toledo, Ohio.
STRUSS, KARL (M)
1343 N. Orange Grove Ave., Holly-
wood, Calif.
STUBBE, GERHARD (4)
American Askania Corp., 809 M. &
M. Bldg., Houston, Texas.
SUBEDAR, JAMNADAR CHOTALAL (^4)
Shree Ranjit Film Co., Dadar Main
Road, Dadar, Bombay, India.
SUGUIRA, ROKUEMON (M)
R. Konishi & Co., 18 Honcho, 2-
Chome, Nihonbashiku, Tokyo,
Japan.
SUMNER, STANLEY (M}
University Theater, Cambridge,
Mass.
SUNDE, HAROLD E. (A)
RCA Victor Co., Camden, N. J.
SWAAB, M. L. (A}
5038 Chestnut St., Philadelphia, Pa.
SWARTZ, E. M. (A)
Keystone Mfg. Co.. 288 A St.,
Boston, Mass.
SWIST, THOMAS P. (A)
306 Ldwell St., Manchester, N. H.
TASKER, HOMER G. (M)
United Research Corp., 41-39 38th
St., Long Island City, N. Y.
TAYLOR, JOHN B. (M)
General Electric Co., Schenectady,
N. Y.
TEITEL, ALBERT (A)
Protecto Films, Inc., 105 W. 40th St..
New York, N.Y.
TERRANEAU, RANDAL (M)
Geo. Humphries & Co., 10 North-
court, Chitty St., Tottenham
Court Rd., London, W. 1, Eng-
land.
TERRY, ROY V. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
THAYER, WM. L. (4)
Paramount Publix Corp., 5451 Mara-
thon St., Hollywood, Calif.
170
LIST OF MEMBERS
[J. S. M. P. E.
THEISEN, EARL (A)
508 S. Union Drive, Los Angeles,
Calif.
THEISS, JOHN H. (M)
35 Linden Ave., Metuchen, N. J.
THOMAS, WILLIAM F. (A)
352 S. Drexel Ave., Detroit, Mich.
THOMPSON, LINCOLN (M)
Wm. H. Bristol Talking Pictures
Corp., Waterbury, Conn.
TILTZ, BERNARD E. (M}
Tiltz Engineering Co., 480 Lexing-
ton Ave., New York, N. Y.
TOUZE, GEORGES 04)
First National Pathe, Ltd., 103
Wardour St., London, W. 1, Eng-
land.
TOWNSEND, LEWIS M. (A)
125 Merchants Road, Rochester,
N. Y.
TRONOLONE, CHARLES (M)
Consolidated Film Industries, Inc.,
1776 Broadway, New York, N. Y.
TRONOLONE, NICK (M}
Consolidated Film Industries, Inc.,
203 W. 146th St., New York, N. Y.
TsucHmAsm, HARUO (.4)
88 Shimpoin-cho, Tenneji-ku, Osaka,
Japan.
TUCKER. Louis B. 04)
Tucker Picture Co., 25 Sackville St.,
Port of Spain, Trinidad, British
West Indies.
TULPAN, SAMUEL 04)
H. E. R. Laboratories, Inc., 437 W.
46th St., New York, N. Y.
TUTTLE, CLIFTON M. 04)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
TUTTLE, H. B. (M)
Eastman Kodak Co., 343 State
Street, Rochester, N. Y.
UNDERBILL, Jos. L. 04)
RCA Photophone, Ltd., Film House,
Wardour St., London, England.
VAUGHAN, RAY (M)
Filmcraft Labs., 35-39 Missenden
Rd., Camperdown, Sydney, Aus-
tralia.
VENTIMIGLIA, GAETANO 04)
Via Emanuele Filiberto, 100, Rome,
Italy.
VICTOR, A. F. (M)
Victor Animatograph Co., 242 W.
55th St., New York, N. Y.
VOLCK, A. GEORGE (M}
6627 Emmett Terrace, Hollywood,
Calif.
VOLTAM, WM. J. (A)
71 Piermont St., Wollaston, Mass.
WADE, FREDERICK H., 04)
Warner Bros. Pictures, Inc., 1277 E.
14th St., Brooklyn, N. Y.
WADDINGHAM, A. G. (M)
PhotocolorCorp., Irvington-on-Hud-
son, N. Y.
WAIDE, MERRILL (M)
General Pictures, Inc., 43-77 Ver-
non Ave., Long Island City,
N. Y.
WALL, JOHN M. (M)
J. M. Wall Machine Co., 101 Court
St., Syracuse, N. Y.
WALLER, FRED (M)
R. F. D. No. 3, Huntington, L. I.,
N. Y.
WARD, ERWIN J. 04)
553 De Nise Road, Rochester, N. Y.
WARMISHAM, ARTHUR 04)
Bell & Howell Co., 4045 N. Rock-
well St., Chicago, 111.
WASCHNECK, KURT (M)
Aktiengesellschaft fur Film Fab-
rikation, Victoriastr., 13/18, Ber-
lin-Tempelhof, Germany.
WATKINS, STANLEY S. A. 04)
Western Electric Co., Bush House,
Aldwych, London, W. C. 2, Eng-
land.
WATSON, J. S., JR. 04)
6 Sibley Place, Rochester, N. Y.
Feb., 1933]
LIST OF MEMBERS
171
WEBB, H. W. (M)
211 Glenwood Ave., Leonia, N. J.
WEBER, CARL M. (M)
Weber Machine Corp., 55 Bengal
Terrace, Rochester, N. Y.
WELMAN, VICTOR A. (A)
207 Finance Bldg., Cleveland,
Ohio.
WENTE, EDWARD C. (M)
Bell Telephone Laboratories, 463
West St., New York, N. Y.
WENZ, AUGUST (4)
Warner Bros. Pictures, Inc., 1277 E.
14th St., Brooklyn, N. Y.
WESTWATER, WALDO (A)
Research Laboratories, Eastman Ko-
dak Co., Rochester, N. Y.
WHITE, D. R. (M)
Du Pont Film Mfg. Co., Parlin,
N.J.
WmTMORE, WILL (^4)
Western Electric Co. 50 Church
St., New York, N. Y.
WILD, GEORGES (A)
22 Rue Cambaceres, 'Paris, VIII,
France.
WILDING, NORMAN E. (A)
7635 Grand River Blvd., Grand
River, Mich.
WILDUNG, F. H. (A)
1920 S St., Washington, D. C.
WILLMAN, RICHARD C. (A)
RCA Photophone, Inc., c/o Inter-
national General Electric Co.,
Stephen House, Dalhousie Square,
Calcutta, India.
WILLIFORD, E. A. (M)
National Carbon Co., Box 400,
Cleveland, Ohio.
WILMOT, H. TAYLOR (A)
5657 Sunset Blvd., Hollywood, Calif.
WILSON, JAMES (A)
72 Penryhn Ave., Walthamstow,
London, E. 17, England.
WILSON, STUART K. (A)
12 Whitehall Rd., Harrow, Middle-
sex, England.
WINN, CURTIS B., JR. (A)
421 E. J St., Ontario, Calif.
WlNTERMAN, CLEMENCE (A)
Topical Film Co., Brent Laborato-
ries, Ltd., North Circular Road,
London, N. W. 2, England.
WISE, ANTHONY G. (If)
8970 Kelson Ave., Los Angeles, Calif.
WOLF, SIDNEY K. (4)
Electrical Research Products, Inc.,
250 West 57th St., New York. N.Y.
WOLFERZ, ALFRED H. (A)
Weston Electrical Instrument Corp.,
Newark, N. J.
WOODS, FRANK E. (M)
Academy M. P. Arts & Sciences,
7046 Hollywood Blvd., Hollywood,
Calif.
WORSTELL, R. E. (4)
General Electric Co., Nela Park,
Cleveland, Ohio.
YAGER, GEORGE A. (4)
167 N. W. Temple St., Salt Lake
City, Utah.
YAGER, H. BARTON (^4)
61 Morton St., New York, N. Y.
YATES, E. C. (A)
Capitol Theater, Singapore, Straits
Settlements.
YOUNG, AL (M)
Du-Art Film Laboratories, Inc.,
245 W. 55th St., New York, N. Y.
ZERK, OSCAR U. (M)
3206 Palmolive Bldg., Chicago, 111.
ZIEBARTH, C. A. (If)
Bell & Howell Co., 1801 Larchmont
Ave., Chicago, 111.
ZOELTSCH, W. F. (A)
461 Central Ave., Union City, N. J.
ZUBER, JOHN G. (A)
Bell & Howell Co., 1801 Larchmont
Ave., Chicago, 111.
ZUCKER, FRANK C. (A)
700 W. 175th St., New York, N. Y.
BOOK REVIEW
Photocells and Their Application. V. K. ZWORYKIN AND E. D. WILSON.
John Wiley and Sons, New York, N. Y., Second Edition, 1932, xv + 331 pp.
(180 Figures). $3.00. This book is an extensive revision of the former edition
published in 1930. More than one hundred and twenty pages have been added,
by including five new chapters and adding considerably to the existing chapters.
Important new data have been interspersed throughout the text, the value of
the book thus being considerably enhanced for the average reader.
Works on photoelectricity seem prone to one of two extremes. Either so
much information is omitted that the book seems sketchy and of limited value,
or so much detail is incorporated that reading becomes difficult unless one is an
authority on the subject. It seems to the reviewer that the authors have avoided
both extremes in the second edition and have produced a work that is very
readable in addition to its being useful for consultation with its very complete
references and bibliography.
This edition follows the same general arrangement as the previous one. The
first two chapters on history and general theory are substantially unchanged.
The third chapter on photosensitive films is new and constitutes a short resume
of this important subject. The next two chapters describe the materials and
apparatus used and the technic followed in constructing the vacuum and gas-
filled cells whose characteristics are described in the succeeding two chapters.
Photoconduction and photovoltaic cells are treated much more fully than in
the previous edition, where they were limited to one short chapter, now expanded
into two. The new dry or sperrschicht cells, which have attracted so much
attention recently, are discussed under the subject of voltaic cells. The three
chapters, ten to twelve, lead the reader from considerations of photo-output and
amplifying tubes and the optimum output of various types of cells, through the
problem of amplification and carrier modulation by various means. The re-
maining seven chapters constitute a comprehensive review of such applications
as special light-sensitive devices, photometry and colorimetry, sound movies,
facsimile transmission, television, miscellaneous uses, and probable future ad-
vancement. E. F. KINGSBURY
172
SOCIETY OF MOTION PICTURE
ENGINEERS
OFFICERS
1933
President
A. N. GOLDSMITH, 570 Lexington Ave., New York, N. Y.
Past-President
J. I. CRABTREE, Eastman Kodak Company, Rochester, N. Y.
Vice-Presidents
E. I. SPONABLE, Fox Film Corp., New York, N. Y.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
Secretary
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
Treasurer
H. T. COWLING, Rochester, N. Y.
Board of Governors
H. T. COWLING, 311 Alexander St., Rochester, N. Y.
J. I. CRABTREE, Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
P. H. EVANS, Warner Bros. Pictures, Inc., 1277 E. 14th St., Brooklyn, N. Y.
R. E. FARNHAM, General Electric Co., Nela Park, Cleveland, Ohio.
O. M. GLUNT, Bell Telephone Laboratories, Inc., New York, N. Y.
A. N. GOLDSMITH, 570 Lexington Ave., New York, N. Y.
W. C. HUBBARD, General Electric Vapor Lamp Co., Hoboken, N. J.
R. F. MITCHELL, Bell & Howell Co., 1801 Larchmont Ave., Chicago, 111.
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
E. HUSE, Eastman Kodak Co., 6706 Santa Monica Ave., Hollywood, Calif.
L. C. PORTER, General Electric Co., Nela Park, Cleveland. Ohio.
E. I. SPONABLE, Fox Film Corp., 850 Tenth Ave., New York. N. Y.
173
174
COMMITTEES
[J. S. M. p. E.
COMMITTEES
1933
W. T. CRESPINEL
R. M. EVANS
Color
P. D. BREWSTER, Chairman
J. F. KlENNINGER
N. M. LA PORTE
G. E. MATTHEWS
H. B. TUTTLE
W. C. HUBBARD
Convention
W. C. KUNZMANN, Chairman
J. H. KURLANDER
M. W. PALMER
J. CRABTREE
J. I. CRABTREE
A. S. DICKINSON
G. EDWARDS
T. FAULKNER
Development and Care of Film
R. F. NICHOLSON, Chairman
A. Hi ATT
D. E. HYNDMAN
E. D. LEISHMAN
C. L. LOOTENS
K. MAClLVAIN
D. MACKENZIE
J. S. MACLEOD
H. RUBIN
W. SCHMIDT
V. B. SEASE
J. H. SPRAY
W. CLARK
O. B. DEPUE
Historical
C. L. GREGORY, Chairman
N. D. GOLDEN
C. F. JENKINS
G. E. MATTHEWS
O. NELSON
T. RAMSAYE
D. M. BALTIMORE
B. W. DEPUE
C. D. ELMS
R. EVANS
E. R. GEIB
G, A. CHAMBERS
B. W. DEPUE
O. B. DEPUE
C. L. GREGORY
Membership and Subscription
H. T. COWLING, Chairman
W. H. CARSON, Vice- Chairman
J. G. T. GILMOUR
W. W. HENNESSY
J. KLENKE
W. C. KUNZMANN
E. E. LAMB
J. E. MCAULEY
Museum
E. THEISEN, Chairman
C. F. JENKINS
W. V. D. KELLEY
G. E. MATTHEWS
M. L. MISTRY
T. NAGASE
J. A. NORLING
N. F. OAKLEY
E. C. SCHMITZ
T. RAMSAYE
A. REEVES
F. H. RICHARDSON
A. F. VICTOR
Feb., 1933]
COMMITTEES
175
A. A. COOK
W. B. COOK
H. A. DEVRY
E. GALE
Non-Theatrical Equipment
R. E. FARNHAM, Chairman
E. R. GEIB
N. B. GREEN
H. GRIFFIN
L. A. JONES
J. H. KURLANDER
R. P. MAY
R. F. MITCHELL
A. SHAPIRO
G. A. CHAMBERS
C. DREHER
P. H. EVANS
A. C. HARDY
Papers
O. M. GLUNT, Chairman
E. HUSE
G. E. MATTHEWS
P. A. McGuiRE
D. McNicoL
W. C. MILLER
K. F. MORGAN
C. N. REIFSTECK
T. E. SHEA
H. T. COWLING
J. I. CRABTREE
Preservation of Film
W. H. CARSON, Chairman
A. S. DICKINSON
R. EVANS
C. L. GREGORY
T. RAMSAYE
V. B. SEASE
M. ABRIBAT
L. BUSCH
F. CAHILL
A. A. COOK
G. A. CHAMBERS
C. DREHER
Progress
J. G. FRAYNE, Chairman
J. A. DUBRAY
R. E. FARNHAM
H. B. FRANKLIN
F. S. IRBY
E. E. LAMB
G. E. MATTHEWS
M. W. PALMER
G. F. RACKETT
P. SCHROTT
H. M. STOLLER
S. S. A. WATKINS
J. O. BAKER
T. BARROWS
G. C. EDWARDS
J. J. FINN
S. GLAUBER
Projection Practice
H. RUBIN, Chairman
J. H. GOLDBERG
C. GREENE
H. GRIFFIN
J. HOPKINS
W. C. KUNZMANN
R. H. McCULLOUGH
P. A. McGuiRE
R. MlEHLING
F. H. RICHARDSON
L. M. TOWNSEND
V. A. WELMAN
E. R. GEIB
H. GRIFFIN
J. H. KURLANDER
Projection Screens
S. K. WOLF, Chairman
W. F. LITTLE
A. L. RAVEN
R. T. RASMUSSEN
H. RUBIN
C. TUTTLE
176
COMMITTEES
R. E. FARNHAM
H. P. GAGE
Projection Theory
A. C. HARDY, Chairman
W. F. LITTLE
W. B. RAYTON
C. TUTTLE
F. C. BADGLEY
B. W. DEPUE
Publicity
W. WHITMORE, Chairman
D. E. HYNDMAN
F. S. IRBY
W. C. KUNZMANN
G. E. MATTHEWS
D. McNicoL
M. C. BATSEL
P. H. EVANS
N. M. LA PORTE
Sound
H. B. SANTEE, Chairman
E. W. KELLOGG
C. L. LOOTENS
W. A. MACNA1R
W. C. MILLER
H. C. SILENT
S. K. WOLF
W. H. CARSON
L. E. CLARK
L. DE FOREST
J. A. DUBRAY
P. H. EVANS
R. E. FARNHAM
C. L. FARRAND
H. GRIFFIN
Standards and Nomenclature
M. C. BATSEL, Chairman
A. C. HARDY
R. C. HUBBARD
L. A. JONES
N. M. LA PORTE
D. MACKENZIE
G. F. RACKETT
W. B. RAYTON
C. N. REIFSTECK
H. RUBIN
H. B. SANTEE
V. B. SEASE
T. E. SHEA
J. L. SPENCE
E. I. SPONABLE
S. K. WOLF
L. J. BUTTOLPH
R. E. FARNHAM
Studio Lighting
P. MOLE, Chairman
C. W. HANDLEY
R. F. MITCHELL, Chairman
B. W. DEPUE, Sec.-Treas.
Chicago Section
J. H. KURLANDER
W. J. QUINLAN
O. B. DEPUE, Manager
J. E. JENKINS, Manager
New York Section
P. H. EVANS, Chairman
D. E. HYNDMAN, Sec.-Treas.
Pacific Coast Section
EMERY HUSE, Chairman
G. F. RACKETT, Sec.-Treas.
M. C. BATSEL, Manager
J. L. SPENCE, Manager
C. DREHER, Manager
J. A. DUBRAY, Manager
SOCIETY ANNOUNCEMENTS
BOARD OF GOVERNORS
At a meeting held at the Hotel Sagamore, Rochester, N. Y., January 20, Mr.
L. C. Porter, who held the office of President of the Society during 1922, 1923,
and 1929, and various other offices since 1917, tendered his resignation as a mem-
ber of the Board. Mr. H. Griffin was appointed to serve in his stead until the ex-
piration of his term of office.
Extensive discussion concerning the approaching convention to be held April
24 to 28, resulted in conclusions described below under the heading Spring, 1933,
Convention. Considerable attention was given by the Board to budgetary mat-
ters, including sectional and committee appropriations, to the question of dues
and subscriptions, and to the general relation between the prevailing economic
conditions and the finances of the Society. In order to assist in distributing the
JOURNAL among subscribers, a special plan was devised, offering to the first one
hundred individuals to take advantage of the plan, complete issues of back num-
bers of the JOURNAL. Thus, by subscribing for the JOURNAL for 1933 and 1934, at
a cost of twenty-four dollars, the first one hundred such subscribers will be en-
titled to receive a complete set of JOURNALS for 1930 and 1931, without further
payment except for postage or expressage. This offer is open also to present sub-
scribers who might wish to extend their subscriptions.
Recommendations made by the S. M. P. E. Historical Committee concerning
the requirements for honorary membership were submitted to the Board . These
requirements, after further study, will receive final action at the next meeting of
the Board, to be held on April 23 at New York, N. Y.
The Board was notified of the formation of two new motion picture societies,
namely, the Motion Picture Society of India, and the Magyar Kinotechnikai
Tarsasag. The Society extends to these new organizations its best wishes for success.
Action was taken by the Board on the report of the Committee on Standards
and Nomenclature, published in the November, 1932, issue of the JOURNAL, as
described below under the heading Standards.
SPRING, 1933, CONVENTION
April 24-28, inclusive; New York, N. Y.
At the meeting of the Board of Governors held on October 5 at New York,
plans for the Spring, 1933, Convention were initiated: the meeting is to be held
at New York, N. Y., and of five days' duration — April 24 to 28, inclusive.
Mr. W. C. Kunzmann, chairman of the Convention Committee, assisted by
Mr. H. Griffin, chairman of the Local Arrangements Committee, is proceeding
with arrangements to hold the Convention at the Hotel Pennsylvania, in the
Salle Moderne.
Mr. O. M. Glunt, chairman of the Papers Committee, promises an extremely
interesting schedule of papers; the number of papers to be presented will be
177
178 SOCIETY ANNOUNCEMENTS [j. S. M. p. E.
limited to what can be accommodated in the allotted time without haste or crowd-
ing, a feature that will assist considerably in the selection of papers from the point
of view of technical quality, with less emphasis on quantity. At the meeting of
the Board of Governors on January 20, Mr. Glunt presented a tentative draft of
a proposed papers program for the Spring Convention, which, in its general form
and with suitable recommendations, was approved by the Board. At a meeting
of the Papers Committee to be held in the near future, the proposed program
will be put into a more final form, prior to its being mailed to the membership
of the Society.
An exhibit of newly developed motion picture equipment will be held, as at
past Conventions, which should prove of considerable interest to every one
interested in motion picture engineering. Manufacturers of equipment are
invited to communicate with the General Office of the Society, 33 W. 42nd St.,
New York, N. Y., for information regarding the regulations of the exhibit and
arrangements for space. Charges for space will be made according to the size of
each exhibit and the space occupied by it.
Plans are being made to assist out-of-town visitors to the Convention to pass
an interesting time while in New York, and special film programs and trips of
interest will be arranged for. Full details of the program, including hotel rates
and other pertinent information will be mailed to the members of the Society at a
later date. Members and friends of the Society are urged to make every effort to
attend the Convention.
STANDARDS
At the meeting of the Board of Governors on January 20, the report of the
Standards and Nomenclature Committee, published in the November, 1932,
issue of the JOURNAL, was accepted. In particular, by separate action, the recom-
mendations made in that report, dealing both with 35- and 16-mm. film, were
adopted as motion picture standards to be recommended to the American Stand-
ards Association, in the requisite form, for its approval.
CHICAGO SECTION
At the December meeting of the Chicago Section, held at the plant of Jenkins
& Adair, Inc., Mr. J. E. Jenkins described the new Phonopticon, a lantern-slide
projector employ ing disk records for sound accompaniment, and the Controllo-
phone, an automatic sound reproducer and equipment demonstrator. A new
35-mm. portable sound-on-film recorder was also demonstrated. At the January
meeting, the preliminary report of the Sub-committee on Laboratory Practices,
of the Committee on the Care and Development of Film, was read by Mr. R. F.
Mitchell, chairman, and carefully discussed by all those present.
PROJECTION PRACTICE COMMITTEE
A meeting of this Committee was held at New York, N. Y., on January 18. The
Committee is at the present time engaged in the study of screen illumination, and
is making a series of measurements in a number of theaters that are expected to
furnish data representative of the general conditions existing. Another matter
upon which the Committee is placing great emphasis is the question of inducing
producers to review releases under conditions of illumination comparable with
Feb., 1933] SOCIETY ANNOUNCEMENTS 179
those found in the theaters, so that prints, when projected in theaters, will not be
found too dense to permit adequate screen illumination, although they may have
appeared quite satisfactory when projected in small review rooms with a screen
illumination several times as great as that obtainable in the theater. Chairman
H. Rubin announced that definite action is being taken by producers in adopting
the recommendations of the Committee for improving the visibility of change-over
marks on films, the recommended marks taking the form of black spots surrounded
by clear circles so that they can be easily distinguished by the projectionist
against either a light or dark background. The work of collecting data on the
clearances, tolerances, and tensions of projectors, begun some time ago, is pro-
gressing, and the Committee hopes to have the material sufficiently complete for
presentation to the Society within several months. A new test reel is being de-
veloped by the Committee for the use of exhibitors in testing the adjustments of
their projection equipment. The mere running of this test film in the theater will
provide visual and aural means of detecting misadjustments of the optical system
of the projector, etc., and will also indicate what adjustments are necessary for the
correction of travel ghost, chromatic aberration, sound track adjustments, and
the like. The test film will be presented to the Society at the Spring Convention,
April 24 to 28, at New York, N. Y.
SUSTAINING MEMBERS
Bausch & Lomb Optical Co.
Bell Telephone Laboratories
Burnett-Timken Laboratories
Eastman Kodak Co.
Electrical Research Products, Inc.
National Carbon Co.
RCA Victor Co., Inc.
HONOR ROLL
OF THE
SOCIETY OF MOTION PICTURE ENGINEERS
By action of the Board of Governors, October 4, 1931, this Honor Roll was estab-
lished for the purpose of perpetuating the names of distinguished pioneers who are
now deceased:
Louis AIME AUGUSTIN LE PRINCE
WILLIAM FRIESE-GREENE
THOMAS ALVA EDISON .
GEORGE EASTMAN
JEAN ACME LE ROY
FILM RECORDING EQUIPMENT
Type 3S Com- Single or Double System, Variable
plete Record- Density or Variable Area, Studio
or Portable.
Write or cable for literature
JENKINS & AD AIR, INC.
3333 Belmont Ave.
Chicago, U. S. A.
Cable Address: JENKADAIR
BEAT-FREQUENCY OSCILLATORS FOR MEASURE-
MENTS AND TESTS
AT AUDIO FREQUENCIES
Since the entire audio-frequency range
is covered by rotating a single dial, the
beat-frequency oscillator is extremely
useful for rapid studies of audio-fre-
quency equipment. The General Radio
Company manufactures two models of
beat-frequency oscillators, one for alter-
nating-current operation and the other
operated from batteries.
TYPE 513-B (alternating-current operated) .... $450.00
TYPE 613-A (battery-operated) 210.00
GENERAL RADIO COMPANY
CAMBRIDGE MASSACHUSETTS
PAMPHLETS, BOOKLETS, AND CATALOGUES
Manufacturers of motion picture equipment and supplies are requested to send
to the General Office of the Society copies of their descriptive pamphlets, book-
lets, and catalogues as issued. Notices of the issuance of this material will be
published in the JOURNAL, advising the readers that the material may be obtained
free of charge by addressing the manufacturers named. This editorial service
has been established in order to acquaint readers of the JOURNAL with the com-
mercial developments of the motion picture industry as quickly as they occur.
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
Volume XX MARCH, 1933 Number 3
CONTENTS
Report of the Committee on the Care and Development of
Film:
Sub-Committee on Laboratory Practice
Page
183
199
211
228
236
249
259
263
267
268
271
274
279
Sub -Commit tee on Exchange Practice
Film Recorders A. G. ZIMMERMAN
The Relation between Diffuse and Specular Density
C. TUTTLE
Model Making with Sheet Film Base
K. HlCKMAN AND D. E. HYNDMAN
The Depicting of Motion Prior to the Advent of the Screen. . .
E. THEISEN
The History of Nitrocellulose as a Film Base E. THEISEN
Early Stages of Kinematography C. H. BOTHAMLEY
Book Review
Officers
Committees
Society Announcements
Catalogues Received
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
SYLVAN HARRIS, EDITOR
Board of Editors
J. I. CRABTREE, Chairman
u. DE FOREST A. C. HARDY E. LEHMANN
O. M. GLUNT F. F. RENWICK
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.
Publication Office, 20th & Northampton Sts., Easton, Pa.
General and Editorial Office, 33 West 42nd St., New York, N. Y.
Copyrighted, 1933, by the Society of Motion Picture Engineers, Inc.
Subscription to non-members, $12.00 per annum; to members, $9.00 per annum,
included in their annual membership dues; single copies, $1.50. A discount
on subscriptions or single copies of 15 per cent is allowed to accredited agencies.
Order from the Society of Motion Picture Engineers, Inc., 20th and Northampton
Sts.. Easton, Pa., or 33 W. 42nd St., New York, N. Y.
Papers appearing in this Journal may be reprinted, abstracted, or abridged
provided credit is given to the Journal of the Society of Motion Picture Engineers
and to the author, or authors, of the papers in question.
The Society is not responsible for statements made by authors.
Entered as second class matter January 15, 1930, at the Post Office at Easton,
Pa., under the Act of March 3, 1879.
REPORT OF THE COMMITTEE ON THE CARE AND
DEVELOPMENT OF FILM
SUB-COMMITTEE ON LABORATORY PRACTICE
The following report, reviewing the conditions as actually found at present in the
field, is intended as an introduction to a more detailed and technical study of laboratory
practice, to be reported on later. All the phases of handling and treating both un-
exposed and exposed film in laboratories are discussed, beginning with the testing
of the raw stock as received by the laboratory, passing through the exposing, develop-
ing, fixing, washing, and drying of the film and concluding with duplicating and
several subsidiary operations. Following the initial work of the sub-committee
represented by the studies of existing conditions described in this report, the sub-
committee purposes in the future to report separately on each of the above phases.
OUTLINE
A. Testing
B. Exposing
C. Developing
D. Fixing
E. Washing
F. Drying
G. Conditioning
H. Cutting
/. Printing
/. Duplicating
K. Seasoning
SUMMARY
Testing. When producers of motion pictures began to record sound on film
in addition to the scenes, the problems of processing became more involved.
Factors that had been allowed to vary with impunity had to be maintained
constant, and sensitometric equipment, requiring for its operation trained men,
had to be installed. New emulsions were prepared in the attempt to obtain a
higher quality of picture and sound records.
Exposing. The theory of sensitometry is quite explicit in defining the proper
exposure of the negative. However, no standard rules of exposure can be strictly
adhered to in producing motion pictures owing to the numerous variations in
working conditions and the many special effects desired. The greatest degree
of coordination is required between the cameramen and the laboratory technicians
if the best quality pictures are to be obtained.
183
184 CARE AND DEVELOPMENT OF FILM [j. s. M. P. E.
Developing. In order to increase the quantity of film processed and improve
the quality of the product, machines are now used in all large laboratories for
developing film. Three methods of controlling the process, or various combina-
tions of these three methods, are usually employed: (1) sampling, (2) time and
temperature, and (3) sensitometric. Each of these methods has its own advantages.
Fixing. Alum fixing baths are most commonly used, as they require very
little attention. The motion of the film through the bath usually causes sufficient
agitation of the solution to assure sufficiently complete fixing.
Washing. In most instances the tap water runs directly through the washing
tanks to the drain. In some few locations it may be necessary to cool the water
during the warm season.
Drying. Conditioned air of the proper temperature and humidity is circulated
through the drying cabinets. The curl of the film usually provides an index of
the proper conduct of the drying procedure.
Conditioning. To prevent the accumulating of dust and dirt on the film, only
conditioned air is admitted into the developing, printing, and assembling rooms.
The improvement in the quality of the film, due to guarding it against dirt and
scratches, has more than offset the cost of the conditioning equipment.
Cutting. The introduction of the sound negative demanded a new technic
in cutting and assembling. The addition of music and other kinds of sounds
requires thorough technical training of the cutter.
Printing. Several types of mechanical devices are now used to determine the
proper printing exposure. The uniformity of development that occurs in de-
veloping machines is an important factor that assists in properly determining the
exposure of the negatives. Trained technicians maintain the exposure scales of
the printers constant and uniform.
Duplicating. Special emulsions and printers are used in attempting to match
the quality of the duplicate print and that of the original print. The contrast
can be matched by appropriately developing the film, although graininess may
increase and loss of definition occur.
Seasoning. Many patented methods are in vogue to protect the film and
lengthen its useful life. The most common method of seasoning consists in
applying about the perforations a small quantity of wax, which decreases the
friction and the tendency to tear during the process of projecting the picture.
It is here purposed merely to describe briefly the methods generally
employed by the industry in the development and care of film. Thus,
the committee submits this report to the Society with the desire
that it be considered as an introduction to the reports to follow, in
which the respective operations in this field will be studied indi-
vidually, both from the standpoint of actual practice and from the
existing literature.
At the completion of such a survey of each operation of the pro-
ducers in converting an emulsion into a finished print, and dis-
tributing the print to the exhibitors, the Committee will be in a
Mar., 1933] LABORATORY PRACTICE 185
position to attempt to make recommendations for the standardiza-
tion of laboratory and exchange practice.
On examining the bibliography in this field, it was found to be
extremely lengthy. Thus, rather than attempt to present a general
bibliography in this report, it has appeared advisable to subdivide
and list the literature in later reports with the respective operation to
which it pertains.
In this general discussion, it may frequently appear that the report
includes subjects outside the purview of this sub-committee. How-
ever, it was concluded that any factor such as the characteristic of
the emulsion or the nature of the exposure that might affect the
quality of the finished print should be considered. The quality of
the laboratory work is judged by the release print.
A. TESTING
The proper processing of sound film, when introduced into the
laboratories, necessitated an increase of personnel. The requirements
of the sound engineers could be correctly interpreted and properly
fulfilled only by those familiar with the theory of sensitometry.
Some laboratories realized this fact, and either engaged additional
help or properly trained some of their own employees. Various
types of sensitometers were installed, and sensitometric practice
soon became a part of laboratory practice. The film manufacturing
companies were particularly helpful in supplying and calibrating
equipment and in training the personnel.
After the practice of continually checking and maintaining de-
velopers and printers had been instituted, it became apparent
that frequently variations were introduced by new emulsions.
Checking new emulsions for speed and contrast then became an addi-
tional function of the new department.
Various types of equipment were tried, with more or less moderate
success. Photocell densitometers were developed for the rapid
reading of sound track densities. In most instances, operators have
returned to such standard equipment as a calibrated wedge or Nicol
prism densitometers. Densities are usually read with the emulsion
facing a diffused light. Sensitometric exposures are usually made in
variable time steps with a high-intensity light. Unless otherwise
stated, all reference made in this report to densities and contrast will
imply this type of measurement.
Practically all motion pictures now made in this country are made
186 CARE AND DEVELOPMENT OF FILM [j. S. M. p. E.
on panchromatic negative stock. The process of making film pan-
chromatic consists essentially of adding dyes to the emulsion to ob-
tain the desired spectral response.
With the advent of sound pictures, it became necessary for some
producers to replace the noisy carbon lights with silent incandescent
lamps. The incandescent lamps, the energy radiation of which was
much greater at the longer wavelengths, permitted the emulsion
makers to increase appreciably the speed of their product by in-
creasing the sensitivity of the emulsion to the red end of the spectrum.
This change permitted a decrease of the required lighting and, in
general, resulted in an improvement in quality of the pictures owing
to the closer equivalence of the spectral response of the film to that
of the eye. However, these advantages are not so important on
exterior pictures where many producers continue to use regular
panchromatic stock.
The addition of a gray coating to the film base resulted in the ab-
sorption, by the base, of the light transmitted through the emulsion,
thus preventing the reflection of light back into the emulsion and
additional exposure caused thereby. Approximately sixty per cent
of the negative emulsions now used employ the non-halation gray
base. Emulsion makers are continually improving their product
by increasing the speed, decreasing the grain, and adding to the
general quality of the finished print.
Due to its low cost and uniform characteristics, positive film is
always used for recording sound on a film separate from that contain-
ing the picture. Most productions are made by this double system
in order to permit the selection of a proper emulsion and negative
developer for the sound recording. Numerous new emulsions have
been made in attempts to improve the volume and quality of the
sound records. Emulsions of high gamma infinity have been made
for variable width records, and emulsions with a low gamma infinity
have been made for variable density records. High-speed positive
emulsions have been made for flashing lamp recording to permit the
use of a lower intensity of unmodulated light, thus demanding a
smaller polarizing current and tending to increase the life of the
lamps.
In single system records, where sound and picture are recorded on
the same film, the sound can not be given much consideration.
Both the negative emulsion characteristics and the negative develop-
ment must be confined to those limits that are satisfactory for the
Mar., 1933] LABORATORY PRACTICE 187
picture. The single system of recording is used only when portability
of equipment is more important than high quality of sound. Its
chief use is found in news photography, in which the necessary equip-
ment is materially decreased by having to employ only a single
camera.
Emulsions for printing are low in price, high in contrast, mono-
chromatic in response, slow of speed, and of extremely fine grain
Several hundred prints are frequently made from a single negative.
This permits the manufacturers to produce positive film more eco-
nomically on large-scale production. Film manufacturing losses
increase with the speed of an emulsion. Dye sensitization is unneces-
sary with monochromatic emulsions. It is therefore possible to
obtain positive emulsions for a fraction of the cost of negative emul-
sions.
The positive film must be high in contrast to permit the required
over-all gamma of unity to be obtained without excessive negative
development. As the high speed of the negative entails a coarse
grain, the development is limited to low values of gamma at which the
grain is not objectionable.
Lamps of almost any type or intensity can be used in the printing
machines. Therefore, economy of manufacture chiefly governs the
speed and spectral response of the positive film. The low speed
permissible with positive emulsions permits us to realize the ad-
vantages of fine grain structure.
B. EXPOSING
According to photographic theory, the visual tone scale of a scene
can be matched on a print only when the negative and print are
properly exposed. The region of correct exposure of a particular
emulsion can be determined by plotting the characteristic from the
density readings of a sensitometric strip of the emulsion. If the
density be plotted against the logarithm of the exposure, the region
of correct exposure will be a straight line. On a negative picture,
developed with a sensitometric strip, those portions of the scene that
produce densities that fall along the straight line are properly ex-
posed. Theoretically all other portions are either overexposed or
underexposed. This is true also of the print.
In practice, the improper exposure of a negative is easily detected
by inspection. If details be lacking in the shadows, the film is under-
exposed; or, if it be lacking in the highlights, the film is overexposed.
188 CARE AND DEVELOPMENT OF FILM [j. S. M. p. E.
Since it is extremely difficult to reproduce faithfully the complete
range of tones visible in the usual scene, the exposure is adjusted
for the objects of principal importance. As the time of exposure
of all sound pictures must be constant, the exposing light must be
adjusted so as to obtain the proper exposure. Trained cameramen
seldom fail to expose their film properly when they are working under
normal conditions. It is much more difficult, however, to achieve
the proper lighting contrast. Often a cameraman returns to a set
for the purpose of photographing additional scenes or making re-
takes after a lapse of several weeks. He must attempt to duplicate
his previous lighting so that his new negatives will properly match the
previously exposed negatives, both in density and contrast. A
change of light intensity in printing can often compensate for a change
of negative density, but a change of contrast can be corrected only by
varying the negative development.
The usual procedure followed in photographing a scene is for the
director to describe to the cameraman the lighting effects desired on
the screen when the print is projected. The cameraman attempts to
accomplish what the director desires by adjusting the positions of his
light sources, the intensity of the light, the color of the light, and the
amount of diffusion. These adjustments are based on his experience
with numerous scenes photographed under various lighting conditions,
which he had subsequently viewed on the screen. The cameraman
must be very familiar with the characteristics of both the negative
emulsion and the manner of developing in the laboratory. If he
makes an error in judging the lighting of the set, the laboratory may or
may not be able to help him, depending upon the type of negative
development control employed.
There are three principal methods of exposing sound negatives. In
the variable width system, a mirror attached to a vibrating gal-
vanometer unit reflects a beam of light upon the moving film, pro-
ducing a sound track of varying width. There are two methods of
exposing variable density sound tracks. In one case, a light beam of
constant intensity impinges upon the moving film through a slit,
the variation of whose width changes the time of exposure. In the
second, the film is exposed to a modulated light beam through a
slit of fixed width and the intensity of the exposing light is varied.
In variable density recording, the same rules concerning exposure
apply as in exposing a negative picture. Overexposure or under-
exposure of the sound track causes audible distortion just as similar
Mar., 1933] LABORATORY PRACTICE 189
errors made in exposing the picture negative cause visible distortion.
Improper exposure in variable width recording does not usually re-
sult in distortion, but causes a change of volume.
In photographing a scene by the double system, a strict routine is
followed to insure the proper marking of the film and thus enable the
laboratory to print the sound and picture negatives in synchronism.
At a signal from the director, the sound machine and camera are
started on an interlocked system. The sound man or his assistant
indicates when his machine has reached synchronous speed. The
assistant cameraman announces the feature, scene, and "take"
numbers before the microphone. Action follows until the cameras
are stopped at a signal from the director. With the cameras and
sound machine still interlocked, the cameraman and sound man
make synchronizing marks on their respective films. The sound man
also punches the feature, scene, and take numbers on his film. The
cameraman photographs a slate bearing the same information. The
films are now completely equipped with identifying marks.
The routine of different companies varies somewhat in obtaining
the same results. Some companies, in preference to making syn-
chronizing marks, photograph the action and record the sound of
some simple device, such as that made by two pieces of wood struck to-
gether. The cutter soon learns to recognize the sound record of this
signal noise as a synchronizing mark on the sound track.
C. DEVELOPING
All developing done by the major laboratories is now accomplished
in machines in which the film is mechanically moved through the
developer at constant speed. The exposed film is fed to the machine
at one end; and the developed, fixed, and dried film is emitted at
the other end. Since many of the laboratories designed their own
machines to suit their specific requirements, numerous types are
found in operation. They may be roughly divided into two classes:
those in which the film moves perpendicularly, and those in which it
moves horizontally.
The developer is continuously circulated through a cooling system.
In some machines thermostats automatically maintain the tem-
perature constant within one degree. The temperature of operation
varies at different laboratories from 65°F. to 68°F. The developer is
maintained at a given strength by automatically introducing addi-
tional developer into the circulating system.
190 CARE AND DEVELOPMENT OF FILM [J. S. M. P. E.
Considerable variation can be found in the speed at which the
film travels through the developer in different developing machines.
While the average speed for negative film is about sixty feet per
minute, speeds as low as twenty feet per minute and as high as one
hundred feet per minute can be found at various laboratories.
Similarly, the time of development of negatives varies from eight
to twenty minutes, depending upon the agitation, rate of circulation,
and strength of the developer. Negative developing gammas vary
from 0.50 to 0.65.
Although the negative developers used in different laboratories
vary in concentration, their basic constituents are usually identical:
monomethyl-para-aminophenol sulfate, hydroquinone, borax, and
sodium carbonate. The concentration of these ingredients is varied
to permit the most efficient operation of the different machines.
When, due to lack of space, a laboratory is obliged to use a small
machine, it is necessary to use a fast working developer in order to
obtain the proper contrast, unless the laboratory is willing to operate
at lower efficiency and operate the machines more slowly.
Three types of control of negative development are in use. In the
time-and-temperature system, all negatives, regardless of exposure,
are developed for a fixed length of time. The bath is supposedly
maintained at a constant strength and constant temperature. The
strength of the bath is checked at regular intervals by means of what
is supposed to be a standard exposed negative.
In the sampling system, the cameraman submits a sample negative
of every new scene, which is developed for a standard length of time.
By inspection of the developed sample, the proper time of develop-
ment of the particular scene is determined. This method places
considerable responsibility on the inspector, who must always be in
close contact with the cameraman in order to know the type of picture
desired.
Sensitometric control is used as a third method of controlling the
development of negatives. Sensitometric strips are inserted at fre-
quent intervals to determine precisely the contrast of development
and the density obtained from a given exposure. These factors are
maintained constant by varying the time of development or by in-
creasing the rate of flow of additional or fresh developer into the
circulating system. The usual practice, followed when the con-
trast or density is found to have changed appreciably, is to vary,
first, the time of development. This correction, which causes im-
Mar., 1933] LABORATORY PRACTICE 191
mediate results, can be realized either by varying the speed of the ma-
chine or by changing the length of the film in the developer. This
second method of making the correction consists in varying either
the lengths of the loops of film in the developer, or in changing the
number of loops. The rate of flow of additional or fresh developer
is then adjusted so that the developer soon returns to its normal
strength. The machine is then readjusted for normal operation.
Due to the numerous adverse conditions that a cameraman must
continually face, it is necessary that the laboratory assist as much as
possible toward obtaining a good negative. While it is not very
desirable, in order to obtain perfect negatives, to have to compensate
for excessive or insufficient exposure, it is possible and often practi-
cable to compensate for excessive or insufficient contrast. Thus,
in a laboratory in which the sampling method is used, it is frequently
possible to match approximately negatives that have been exposed
under different lighting conditions. For very flat lighting, the de-
velopment is increased; and for very contrasty lighting, the develop-
ment is decreased. Of course, the negative development must not
be increased to such an extent as to permit the negative grain to be-
come objectionable. Extreme care must be taken at the laboratory to
interpret correctly the lighting effects desired by the cameraman and
director. The cameraman should always be advised of any variation
made in his favor to aid him in future lighting.
Although positive emulsions are used for variable density sound
negatives, they are usually developed in a negative bath. This is a
low gamma bath, which permits a reasonable developing time for
the desired low contrasts of 0.40 to 0.55. An exception to this occurs
when developing negatives recorded by the flashing lamp, in which
case the records are frequently developed with the regular prints to a
gamma of 2.0 to 2.2. This high negative development tends to
correct the distortion due to the underexposure. The volume level
of the signal on the print also increases with the negative develop-
ment.
In variable width records it is highly desirable to develop the
negative to the full extent if the maximum volume is to be obtained.
Frequently a special high gamma developer is employed, and gammas
as high as 3.0 are found.
The usual bath employed in developing prints is of the type em-
ploying monomethyl-para-aminophenol sulfate and hydroquinone.
The desired contrast of development varies from 1.80 to 2.20. The
192 CARE AND DEVELOPMENT OF FILM [j. S. M. P. E.
permissible variation during operation is approximately five per cent.
It is extremely important that the density obtained in the positive
bath after a given exposure remain constant. Frequently orders
come to the laboratory for reprints of negatives that have been timed
several weeks, or even months, previously. If originally the bath
had been properly maintained and if the new bath is made to match
the original bath properly, it becomes possible to use the old printing
cards that indicate the proper printing step for each negative scene.
If, on the other hand, the strength of the original bath had been al-
lowed to vary, the negatives made in later baths would require retiming
for all reprints and the timer would never be certain of his results.
Sensitometric exposures are usually employed to check the con-
trast and density obtained in the positive bath. However, a print
made from a standard negative and a standard printer is also used as
an additional visual check.
Positive developing machines are usually constructed to run at
higher speeds than negative developing machines. The printed film
is not as valuable as the negative, and in case of damage it can easily
be replaced. Due to the brevity of time between completing the
photographing of a picture and releasing it, it is usually necessary to
operate the positive machines at high speeds in order to adhere to the
laboratory's schedule.
The average speed of the positive machines is about 110 feet per
minute. Some laboratories develop as much as 150 feet of film per
minute, while others develop as little as 80 feet per minute. The tem-
perature of the bath is maintained constant within a degree. The
average operating temperature is about 66°F. The time of develop-
ment varies from three and a half to eight minutes, depending upon
conditions.
D. FIXING
Most laboratories use an acid or a chrome alum fixing bath.
An acid bath must be watched so as to guard against precipitation,
which may cause an undesirable deposit on the film. In general
practice, the fixing solution is neither mechanically circulated nor
thermostatically controlled. The temperature of the room and the
proximity of the washing tanks are sufficient to maintain the tem-
perature below 68° F. When the temperature is allowed to exceed
70 °F., the grain of the film increases and sulfur dioxide may be
released. The motion of the film through the solution causes suf-
ficient agitation for proper fixing.
Mar., 1933] LABORATORY PRACTICE 193
The strength of the fixing bath is checked by noting the point in
the machine at which the film becomes clear. When this point
approaches the vicinity of the wash tanks, the solution is strengthened
by replacing some of it with fresh solution.
The average time of fixing negative film varies from 8 to 12 minutes.
Several minutes less are sufficient for fixing positives.
E. WASHING
Wash water is usually obtained directly from the main supply.
In some instances during warm seasons, some rough method of
cooling may be required. Normally, however, the temperature of the
tap water does not exceed 70 °F., which is satisfactory for washing.
The water flows continuously from the main into the wash tanks,
and thence to the drain.
A chemical test is frequently employed to determine whether the
film has been sufficiently washed. The drippings from the film
can easily be tested for the presence of hypo by adding a solution of
potassium carbonate and potassium permanganate in water. A
greenish yellow color results when hypo is present. The average
time of washing negative film varies from 10 to 15 minutes. Several
minutes less of washing are sufficient for positive film.
F. DRYING
Since the universal adoption of machine methods of developing
film, the drum method of drying is no longer used. By the modern
methods, film is dried in cabinets through which conditioned air
circulates. The relative humidity of the air is maintained at ap-
proximately 40 per cent, at a temperature of about 73 °F. In some
instances, when the machines are required to operate at maximum
capacity, temperatures as high as 110°F. are necessary in order to be
sure that the film becomes sufficiently dry. However, it is con-
sidered poor practice to operate under such conditions, 85°F. being
supposedly the optimal temperature for drying.
The rate of flow of air required for complete drying depends upon
the construction of the cabinets, the position of the baffles, and other
variables. An operator constantly checks the drying of the film
by inspecting the curl of the film through the glass doors of the drying
cabinets.
G. CONDITIONING
Laboratories have found it necessary during the last few years
to be equipped with high-grade air conditioning systems. All dust
194 CARE AND DEVELOPMENT OF FILM [j. s. M. p. E.
particles must be removed from the air admitted to the developing,
printing, and assembling rooms, and particularly from the air forced
through the drying cabinets. The temperature and humidity of the
air in the drying cabinets are also maintained constant. Automatic
temperature and humidity controls are installed in order to maintain
the proper drying conditions regardless of the exterior atmospheric
conditions. The temperature and humidity of the air in some of the
laboratory workrooms are also controlled ; particularly in the printing
room, where a relative humidity of 65 to 70 per cent, at a temperature
of approximately 70 °F., is maintained in order to prevent the static
discharges that sometimes occur when exposing raw emulsions.
The cycle of air conditioning is roughly as follows : Air is admitted
through a vent into a heating chamber. After a suitable adjustment
of the temperature, it is mixed with the air that is being recirculated.
It is then forced through an automatic filter into the water spray
chamber, where the air is washed and given the proper temperature
and humidity. The air is drawn from this chamber, forced into the
ducts, and distributed. In addition to this air conditioning unit,
a heating system and a refrigerating unit are also required.
H. CUTTING
After being properly dried, the sound and picture negatives are
cut into single takes and properly marked for printing. The marks
are so made as to compensate for the approximate 15- inch displace-
ment required by the projector for synchronized reproduction.
A complete list of all takes is submitted to the laboratory by the
cameraman. This list aids the cutter in assembling and marking
the film, and furnishes advice to the laboratory as to which negatives
are to be printed. Numerous takes are spoiled, due to improper
action, which are not printed. Rush prints of all desirable takes are
usually made immediately following the negative development to
permit screening by the director on the day following the photograph-
ing. After screening, the rush prints are handed to the positive
cutter, who cuts, assembles, and selects the scenes as advised by
the director. After all the scenes have been photographed and the
rush prints have been cut and assembled into a complete print satis-
factory tp the director, the print is handed to the negative cutters,
who cut and assemble the sound negative to match the rush print.
A complete new sample print is then made, which is cut and re-
assembled until the director and producers are completely satisfied.
Mar., 1933] LABORATORY PRACTICE 195
The negative is again cut to match the corrected print, and a second
sample print is produced. Titles, fades, musical accompaniment,
and extraneous sounds are all added before the second sample is
printed. If the second sample is entirely satisfactory, the picture is
ready for release printing.
Producing companies usually have a production laboratory in the
vicinity of the studio and a release laboratory at the distribution
center. The second sample print is sent immediately upon comple-
tion to the release laboratory, together with the sound and picture
negatives. This permits the distributing officials to inspect the
picture before making the release prints.
I. PRINTING
The negatives can be timed and the proper printer step on which
to expose a given negative can be determined by inspecting the
negative. An experienced timer can determine the step on which
the negative should be exposed in order to obtain a high quality
print simply by inspecting the density of the negative. However,
most laboratories also use an exposing device, either for the purpose
of checking the timer or for use in emergencies. Such a device is so
constructed as to obtain simultaneously a series of exposures that
match, respectively, points over the entire printer scale. Thus,
a negative can be timed by printing in such a device, and developing,
this short sample strip. The proper step can then be easily deter-
mined by inspection. As was mentioned in connection with the
developer, the timer must also be advised of the lighting effects in the
picture that the cameraman is attempting to obtain.
Most negatives, notwithstanding the careful handling in air
conditioned rooms, require a thorough cleaning before printing.
Several simple cleaning devices have been tried and some are still
in use. Most negatives, however, are still cleaned by hand with
carbon tetrachloride. Both sides of the film are firmly wiped with a
saturated pad of velvet or some other soft cloth. As the vapor of
carbon tetrachloride is unpleasant, drafts are provided. The vapor
is heavier than air, so down drafts are recommended. The fre-
quency of cleaning necessary during printing depends upon the main-
tenance of the rooms and machines. Usually the negatives are
cleaned after a dozen prints have been made.
In some laboratories, the printers are fitted with suction devices
for cleaning the raw stock. Dust particles or any other particles that
196 CARE AND DEVELOPMENT OF FILM [J. S. M. P. E.
might have been deposited upon the emulsion are removed. The
illumination of the modern printing room is more than sufficient for
efficient machine operation. Properly filtered light, and white walls,
can provide satisfactory uniform illumination without fear of fogging.
Two types of printers are employed in picture printing: step
printers and continuous printers. The laboratories using step
printers claim that, due to the better contact, the definition obtained
on such printers is superior to that obtained on continuous printers.
Those using continuous printers may or may not admit this ad-
vantage of the step printer, but they state that .the increased speed
and the ability to print either sound or picture more than com-
pensate for a small loss of definition. Step printers run at rates
varying from 20 to 70 feet of film per minute, while continuous
printers operate at 65 to 100 feet per minute. The number of breaks,
the damage caused by a break, and the wear and tear on the negative
increase with the speed of printing.
Approximately half the laboratories have adapted their printers to
permit the simultaneous printing of sound and picture films. This
requires a second printing aperture and light source, as well as addi-
tional incidental equipment. Some few machines have been modified
to permit forward and backward printing.
For newsreels, both picture and sound are printed on continuous
machines. Usually the picture is printed first, the sound being
properly displaced and printed after rewinding. The newsreel
negative is cut into lengths of approximately one hundred feet.
This permits a number of printing machines to be used, and consider-
ably decreases the time of printing.
J. DUPLICATING
Many methods of duplicating can be found in practice. Special
duplicating stocks have been manufactured to aid the laboratories to
produce duplicate negatives that are exact replicas of the original
negatives.
A positive emulsion with a lavender base is most commonly used
for master positives. The colored base serves to identify the emul-
sion, and acts as a filter when the duplicate negative is exposed.
A special negative duplicating emulsion is made, which incorporates
a yellow dye. The effect of the dye is to retard the penetration of
the light, and to cause the image to be maintained on the surface
of the emulsion.
Mar., 1933] LABORATORY PRACTICE 197
In some instances, regular positive stock is used for both master
positives and duplicate negatives, whereas in other laboratories
the duplicate negative emulsion is used for both purposes. When
the identical emulsion is used for master positives and duplicate
negatives, it receives equal development in each case. Since the
development gamma product of the master positive and the duplicate
negative should lie in the range 0.90 to 1.00 in order to reproduce
correctly the original negative, the respective development gammas
are approximately 0.95.
The latest experimental results indicate that the highest quality
duplicates are obtained by using the lavender duplicating positive
and the yellow-dyed duplicating negative. The former is developed
in a positive bath to a gamma of 1.80 to 1.90, and the latter is de-
veloped in a borax negative bath to a gamma of 0.50 to 0.60.
In picture duplicating, step printers are frequently used. Fast
printing is unnecessary, and losses of definition are cumulative.
Excellent duplicates have been obtained, however, on both step and
continuous printers.
Sound records can be successfully duplicated in the same manner
as a picture. Many companies prefer to re-record the sound, as a
small percentage of the high frequencies is lost in printing, due to poor
contact and slippage. In re-recording, it is possible to equalize any
desired portion of the frequency range.
K. SEASONING
Numerous systems are advocated for treating release prints chemi-
cally or physically in order to increase the life of the prints and elimi-
nate projection difficulties. When new prints are projected there
is a strong tendency for the emulsion to deposit on the tension shoes
or aperture plate of the projector. The result is that abnormal
forces are caused to act on the perforations, and the film may be
seriously damaged. As this difficulty disappears after the print has
been projected several times, it is desirable to treat the new prints
by some method that will give them the same characteristics as
prints that have been projected a number of times.
In one system the gelatin is caused to swell, thus permitting to be
introduced into it substances that harden the surface and cause a
glossy finish. After receiving such a treatment the film is supposed
to be able to resist successfully any normal mechanical attacks.
This method of seasoning requires special laboratory equipment, or
198 CARE AND DEVELOPMENT OF FILM
the film must be sent to a seasoning laboratory. Several other
systems, claimed to effect the same results, involve a patented
solution which is added to the fixing bath.
Although some of these systems appear to have merit, most of the
laboratories are content with edge waxing and buffing. Sometimes
the buffing is omitted, the edge waxing being done automatically as
the film emerges from the drying cabinets.
R. F. NICHOLSON, Chairman
R. C. HUBBARD, Vice- Chairman
• J. CRABTREE D. E. HYNDMAN H. RUBIN
J. I. CRABTREE C. L. LOOTENS W. SCHMIDT
C. DREHER K. MAC!LVAIN V. B. SEASE
R. M. EVANS D. MACKENZIE J. H. SPRAY
R. F. MITCHELL
REPORT OF THE COMMITTEE ON THE CARE AND
DEVELOPMENT OF FILM
SUB-COMMITTEE ON EXCHANGE PRACTICE
The following report, reviewing the conditions as actually found at present in the
field, is intended as an introduction to a more detailed and technical study of exchange
practice to be reported on later. All the phases of handling film in the exchanges are
discussed, beginning with the reception of the release print from the laboratories,
passing through treating and processing, maintenance and inspection, and including
a discussion of the equipment and control of the exchanges. Following the initial
work of the sub-committee, represented by studies of the existing conditions described
in this report, the sub-committee purposes in future reports to deal separately and at
great length with each of these phases individually.
OUTLINE
A . Introduction
B. Laboratory practice
(1) Standard release print
(2) Treating and processing
(5) Capacity of reels
(4) Footage of reels
(5) Mounting of film
C. Exchange practice
(1) Maintenance of film
(2) Storing of film
(5) Shipping routines and records
(4) Housekeeping, and control of fire hazards
(5) Equipment
(6) Home office control
SUMMARY
Introduction. In this, the first report of the Sub-committee on Exchange
Practice, only some few definite recommendations to the entire industry are
made. Included in the report, however, are numerous suggestions that should
prove valuable when individual practice permits their application.
Laboratory Practice. Many difficult problems in exchange practice could be
completely obviated if all laboratory work were correct and complete. Proper
seasoning of the film after developing would increase the life of the print. A more
uniform picture density and sound volume are highly desirable.
Maintenance of Film. New film received by the exchanges should be mounted
on perfect reels and properly identified. All film should be inspected and repaired
199
200 CARE AND DEVELOPMENT OF FILM [j. s. M. P. E
immediately upon its return from the theater. A complete record should be
kept of the condition of each reel of film.
Storing of Film. Film should be stored according to the code of the National
Board of Fire Underwriters, and all local Boards. Temperature and humidity
should be controlled wherever possible.
Shipping Routines and Records. All movements of film should be recorded.
A more uniform method of keeping records throughout the various exchanges
should prove advantageous.
Housekeeping and Control of Fire Hazards. The National Board of Fire
Underwriters and the Department of Conservation of the Motion Picture Pro-
ducers and Distributors of America have formed rules for the handling of film.
These rules should be strictly adhered to by the film exchanges.
Equipment. The desirable types of rewind splicers and other equipment are
listed. Automatic splicing machines have been found to be more satisfactory
than the hand-operated splicing device.
Home Office Control. Proper home office control of exchange office routines
produces satisfactory results.
A. INTRODUCTION
In view of the fact that the film exchanges are inadequately repre-
sented in the membership of the Society, considerable research work
outside the membership of the sub-committee was found necessary,
in order to obtain information on the operating routines of some of
the exchange units of the industry.
In the following report, laboratory practice and projection practice
have been touched upon only so far as was thought necessary to
correlate the work of those phases of the industry and that of ex-
change practice. Those phases include the preparation, by the
laboratory, of the release print for the exchange, and the control by
the exchanges of the film while in the hands of the projectionist.
B. LABORATORY PRACTICE
(1) Standard Release Print. — By adopting the standard release
print, the laboratories have vacated many of the irregularities that
formerly confronted the exchanges, but there yet remain other prob-
lems to be solved with the aid of the laboratories. The variations
of the volume range of sound, and of the density of the printed image
of both the sound and the picture, are purely laboratory problems
in so far as printing is concerned, although they contribute seriously
to the difficulties of the exchanges for the reason that such irregulari-
ties are rarely evident until the first screening of the print in the
theater, when insufficient time remains in which to obtain a replace-
ment print. Standardization by the laboratories in this respect is
highly desirable.
Mar., 1933] EXCHANGE PRACTICE 201
(2) Treating and Processing. — When preparing a print for the
exchange, it is desirable that the laboratory treat it so that:
(1) The pulling or straining of perforations, due to deposits of emulsion on
the tension shoes or aperture plate of the projector be eliminated.
(2) The emulsion be so toughened as to resist scratching of the surface of
the film as far as possible.
(3) The warping and buckling of the film, caused by the heating of the gelatin
by the projection lamp, should be reduced as far as possible.
(4) The pliability of the gelatin and its binder should be as permanent as
possible, so that the useful life of the film may be made at least equal to the
booking period.
(3) Capacity of Reels. — A standard size of reel, agreed to and
used by both the exchanges and the projectionists, must be adopted
for the good of all concerned. The mounting of film in the exchanges
on 1000-foot reels for transportation, the subsequent transferring of
the film to reels holding from 1500 to 3000 feet of film in the projec-
tion room, and the re-transfer to the original 1000-foot reels for re-
turn to the exchange represents a great deal of lost motion. Need-
less time and effort is spent by the projectionist in making such
changes. A like amount of time and effort is lost in the exchange
inspection room in checking the correctness of the footage and of the
heads and tails of the reels.
A large amount of film footage is lost because of this practice,
and either all film should be mounted on large reels in the exchanges,
or projectionists should be forced to discontinue the practice of
mounting two or more reels of film on one large reel.
From an exchange standpoint, the 1000-foot reel is far more desir-
able, owing to the greater ease with which it can be handled and the
greater efficiency with which it can be inspected.
The tensile strength of new film and its elongation properties will
permit reels to be doubled under proper working conditions without
damaging the film; but when the film has become seasoned the
perforation area admits of less elongation than the center of the
film and is, therefore, subjected to the entire strain of the traction
load of the film in the upper and lower magazines.
The braking surface in the upper magazine, for properly controlling
the feed of the film when the double reel is full, causes a tension to be
applied to the later footage of the reel that often is greater than the
elongation of the perforation area permits. The perforations, as a
result, break down.
In the lower magazine, improper adjustment of the friction drive
202 CARE AND DEVELOPMENT OF FILM [J. S. M. P. E.
or the take-up will often cause a similar condition in the early footage
of a reel. The variation of the shaft speed of the take-up, caused by
the increasing of the circumference of the reel as footage is added to
it, is compensated for in a friction drive that must be precisely ad-
justed to drive the take-up steadily when the reel is filled. The
friction required to cause such a steady drive of a full reel is greater
than that required for the incomplete reel; whence there results a
tendency, in the early footage, for the reel to take the film faster than
it is fed out by the lower sprocket.
Insufficient tension on the friction drive of the take-up will halt
the loaded reel momentarily, thus creating a slack in the film between
the take-up reel and the lower sprocket. This slack permits the
take-up drive to operate under no load, and the reel accelerates
ahead of the feed of the lower sprocket, tearing the film at the lower
sprocket when the end of the slack is reached.
Suggesting a remedy for this, the sub-committee believes that it
would be well for the exchanges to consider mounting all film on 1000-
foot reels having 5-inch hubs, instead of on the 1000-foot reels with
the 2-inch hubs now universally used by the exchanges.
Because of the larger hub, the reel can be made considerably
stronger, and a more positive stand can be consistently taken against
the doubling of reels by the projectionists. Such a reel would
vacate two of the faults of the reel now generally used by the ex-
changes that most projectionists offer as reasons for doubling reels:
namely, a uniform reel for use in the upper magazine, and a reel with
a 5-inch hub for the take-up in the lower magazine. This size of
reel could be used without materially changing the present shipping
cases, vault racks, or equipment in the inspection rooms.
The cost of a strongly built reel with a 5-inch hub would be greater
than that of the reel now used; but it is the opinion of the sub-
committee that this difference in cost would be more than offset by
the probable saving of time of inspection, the elimination of doubling
of reels, and the loss of film at the beginnings and ends of the reels.
(4) Footage. — The footage of a reel is usually dependent upon the
editing of the picture, and can not be controlled by the laboratory;
but if a standard approximate length were subscribed to and adopted
by the exchanges and the laboratories, the film cutter could be in-
duced to restrict his editing accordingly. A desirable footage under
the present exchange operating conditions would be approximately
950 feet per reel, a maximum being set at 1000 feet.
Mar., 1933] EXCHANGE PRACTICE 203
The matter of mounting film on metal reels in the laboratory before
shipping to the exchanges, and the shipping of film in metal I. C. C.
shipping cases instead of in the wooden cases now used, can be re-
garded from many points of view. If all film, other than newsreel
releases, were mounted on reels at the laboratory, new reels far in
excess of the number now bought by the exchanges would have to be
purchased, or the return of used reels by the exchanges to the labora-
tories on the obsolescence and dismantling of film would have to
be insisted upon. Such a practice would not offer sufficient ad-
vantages to make it worth while to propose it as a standard of general
practice.
Shipping Cases. — In the matter of containers for shipments: the
cost of the wooden cases now used for shipping film from the labora-
tories to the exchanges is written off after the initial shipment is
received by the exchange, as these cases have no further value.
The greater weight of the metal I. C. C. shipping case, if used,
would increase the carrying charge on the initial shipment so that it
would equal the cost of the wooden case. The practice of shipping
releases in metal I. C. C. cases would make it necessary to return the
cases to the laboratory when final disposition of the film at the ex-
change is made. If a reclamation plant were established, to which all
I. C. C. cases could be sent by all exchanges after final disposition of
the film, a considerable saving could be effected for the industry, as a
large percentage of the metal cases now junked by the exchanges
because of the lack of means of repairing them could be repaired at
such a plant for a small fraction of the initial cost. They could then
be allotted to the various laboratories for subsequent shipments of
new film to the exchanges. Such an arrangement would require a
repair plant at both New York and Hollywood, and cases could be
sent by the exchanges to either plant by freight or express. A carry-
ing charge of 20 cents would be levied on each case sent from any
point in the United States, the express company making a return
charge of 20 cents for any container in which an original shipment was
made by express.
(5) Mounting. — When film is mounted on reels at the laboratory,
film bands bearing the title of the subject and the number of the
reels should be stamped thereon. When unmounted, it is desirable
that the reels be wound with the "tails" outward. A standard
size of flange should be used by both laboratories and exchanges for
mounting or dismounting film.
204 CARE AND DEVELOPMENT OF FILM [J. S. M. P. E.
C. EXCHANGE PRACTICE
Exchange practice involves the routine handling of film during its
exhibition life, and usually it would appear as though most of the
exchanges followed in the main the same operating procedure. A
comparison of the condition of the film of one distributor or ex-
change with that of another shows that such is not the case, and
demonstrates the need of standardizing the operating technic of all
exchanges of all companies.
In assembling the information obtained from the various distribu-
tors on the routine care and maintenance of film, the sub-committee
has endeavored to select and suggest for general adoption those
features thought most amenable to standardization. Distributing
companies that maintain their film in the best condition are those
that are completely controlled by their home offices. It seems to be
desirable that all distributing companies be similarly controlled.
The home office, through its control, should direct the routines of the
exchanges in respect to what is described in the remainder of this
report, and should hold the exchange managers responsible for the
adherence of the exchange to the policies instituted.
(1) Maintenance of Film. — Film received from the laboratory
should be mounted on new reels or on reels that are in perfect condi-
tion. A flange made for the specific purpose should be used and
film bands bearing complete information should be placed around the
film. Film should never be mounted from a flat table, or from a
makeshift flange made from old reels. Under no conditions should a
pencil or other wooden rod ever be used as a hub or spindle in the
center of the reel of film, as a positive fire hazard is created by the
friction of the film rubbing against the wood.
A film record card should be made out for each print, on which is
kept a record of the condition of the film, its location while in the
vaults, full data on playing dates while out of the house, the in-
spector's initials, and the date of each inspection.
Film should be graded as to its condition in the following manner:
No. 1 condition: good in every respect.
No. 2 condition: good; film damaged slightly.
No. 3 condition: film in poor condition.
No. 4 condition: junk film.
As this manner of grading film specifies film that would be acceptable
in any first-class theater as in No. 1 condition, and film unfit for use
as in No. 4 condition, the range of conditions between No. 1 and
Mar., 1933] EXCHANGE PRACTICE 205
No. 4 is very wide. New film can be graded only as No. 1 , and ' 'junk' '
film can be graded only as No. 4; whence it follows that No. 2 film
is considered to be good film, but its acceptance in a class "A" house
would be questionable. Therefore, it is considered good film until
the inspector finds out otherwise and marks it as "3," meaning in
poor condition. Dirt and oil on the film should not be considered in
grading the film, as obviously any grade of film can be dirty or oily,
but be restored to the proper condition by cleaning or process-
ing. The sub-committee feels that it is desirable for every ex-
change to have available a place where dirty and oily film can be
cleaned.
Film can be satisfactorily cleaned by cleaning machines now on the
market. If done in the exchange, it is impracticable to attempt to
clean film by hand. All cleaning fluids should be non-inflammable
and uninjurious to celluloid or gelatin. Carbon tetrachloride can be
used satisfactorily for cleaning film, as can trichlorethylene, but the
use of either requires proper ventilation.
For exchanges that would operate their own cleaning plants, the
sub-committee recommends the use of a machine that submerges the
film in the cleaning fluid, cleans the emulsified dirt and oil from the
film by passing the film through a series of soft rubber squeegees,
and polishes it by passing it over revolving rollers covered with
soft flannel. The machine and the room should be well ventilated.
Film should be inspected and repaired immediately upon being
returned from the theater, and the condition of the film should be
noted and recorded on the "film record card." When undue damage
has occurred to any part of a print, the record card should carry in-
formation of the damage and the name of the theater responsible for
it. The booking manager of the exchange should be furnished with
complete data on the damage, repairs made, and the replacement
parts ordered when necessary.
Inspectors should not be permitted to wear anything on their hands
other than a light cotton glove. While inspecting film, all jewelry
should be removed from fingers and wrists.
All film should be inspected from the left rewind to the right, be-
ginning with the "tail" of the reel outward, so that the inspected film
reel ends on the right-hand rewind with the "start" or head of the
reel outward. As all splices are made by scraping the film on the
left of the damaged part, this routine results in a splice that is better
fitted to pass through the curves and loops and over the sprockets of a
206 CARE AND DEVELOPMENT OF FILM [J. S. M. P. E.
Simplex projector. In splicing, the emulsion should be removed with
a dry scraper. Only fresh film cement should be used. A mechani-
cal splice is recommended, and should always be referred to as a
"splice" and not as a * 'patch."
The inspector should hold the film so that it passes first over the
left hand and then between the fingers. If held so that the film passes
under the left hand before passing through the fingers, all the dirt and
grit that is on the film collects on the palm of the hand and scratches
the remainder of the reel being inspected.
In order to maintain the proper locations of the "change-over"
signals in the standard release print, where these have been altered
by placing the film on 2000-foot reels, the "start" mark should always
be placed at the correct distance ahead of the action. This distance
should be exactly determined in all reels of all prints, and can be
maintained by the film footage numbers in the margin of the film.
When necessary, black leader film should be inserted between the
"start" mark and the first scene of the action in order to maintain
the correct distance.
When splices occur at the ends of reels, shortening the distance
between the "start-motor" signal or the "cut-over" signal and the
end of the action, replacement film should be inserted; or the "start-
motor" signal or the "cut-over" signal should be removed, making
new ones at the proper distance from the end of the action in order to
provide the projectionist with the correct "cut-over" cues. To avoid
mutilation of the film by punch marks, stickers, and scratches, ex-
changes should notify all exhibitors that the only permissible way
of indicating variations from the standard release print markings
would be to use a china marking pencil, and that such marks should
not extend over two frames.
The inspector should examine the marginal footage numbers on
both sides of each splice when inspecting sound film, so as to deter-
mine the probable deletion of footage. If the deletion is large or im-
portant, replacement film is necessary. Companies that do not ad-
here to a distinctive uniform splice should require that each splice
made and examined be stamped with an embossing stamp to signify
that the footage deleted has been "okayed." This precludes the
necessity of a like examination in following inspections.
The inspection should be supervised by a person well informed in
the work, who should always be in close contact with the booking
department, and be responsible to it for the correct maintenance of
Mar., 1933] EXCHANGE PRACTICE 207
the film. Care should be exercised by the personnel department as to
the ability of persons employed to inspect film.
Various forms are necessary in every inspection department: (a)
an individual notebook, maintained by each inspector, showing the
amount of work done daily, the production number or title of each
subject inspected, and the number of reels and their condition.
The supervisor should determine from these notebooks the amount of
work done each day, and should render to the branch manager a
weekly report showing a complete resume of the work; (b) forms for
reporting damaged film to the booking department, to be filled out by
the inspector's supervisor; (c) forms for ordering replacement parts,
to be filled out by the inspector's supervisor, and handed to the
booking department.
(2) Storing of Film. — Film should be stored only in sprinkler-
equipped vaults or cabinets properly vented, and built in accordance
with the code of the National Board of Fire Underwriters, and all
local fire ordinances.
Film that is yet in its booking stage should be filed in film vaults in
the I. C. C. container in which it is shipped to the theater. Film to
be stored permanently should be removed from its reels and filed in
individual approved containers. The sub-committee recommends
that the temperature inside the vaults be kept as nearly at the
temperature of the shipping room as is possible in exchanges through
which film is passing. For storing and preserving film permanently,
the temperature of the air should be maintained approximately at
65°F. to 70°F. at a relative humidity of 65 per cent.
(3) Shipping Routines and Records. — The shipping and receiving
of film and the routine used in these connections can more easily be
standardized than the inspection and maintenance of film, for the
reason that no variations occur in the shipping routines found in
different localities or in small or large exchanges. All movements of
film are recorded on the "film record card." No film of any footage
whatsoever, except scrap film, should be sent from the film room
without an order from the person or department authorized to make
such orders directing its movement. Scrap film should be delivered
only to a person or agency duly authorized by the city authorities to
collect it, and, regardless of quantity, should never be burned in the
basement of the building or in any adjacent lots.
The forms used in shipping and receiving film should include a
daily shipping sheet, made up by the booking department and ac-
208 CARE AND DEVELOPMENT OF FILM [J. S. M. P. E.
companied by individual shipping orders from the accounting de-
partment, shipping labels, caution labels, C.O.D. labels and orders for
shipments to be sent C.O.D., express delivery records, receiving
records, reports for overdue film, and packing slips for return of
"junk" film.
(4) Housekeeping and Control of Fire Hazards. — Conditions and
control of fire hazards in both inspection and shipping rooms, and
in the vaults of an exchange, should be standardized as far as possible.
The sub-committee recommends that the rules governing these
conditions, as laid down by the National Board of Fire Underwriters
and supported throughout and followed up by the Department of
Conservation of the Motion Picture Producers and Distributors of
America, be endorsed by the S. M. P. E. and recommended as stand-
ards of procedure for all exchanges of all companies. The Depart-
ment of Conservation of the M. P. P. D. A. has been following this
work completely and thoroughly, as evidenced by the almost total
elimination of losses by fire in exchanges that are receiving the
benefits of systematic inspection by that organization.
No unauthorized visitors should be permitted in the film rooms
of an exchange. Delivery boys, projectionists, and messengers
picking up film, should not be allowed free access to the film
rooms.
(5) Equipment. — All equipment used in maintaining film and in
shipping and storing it should be standardized for all exchanges as
far as possible, so that a uniform procedure may be followed. Requi-
site equipment of film inspection rooms consists of tables, chairs,
rewinds, mounting flanges, splicing blocks, title cabinet, leader cabi-
nets, waste film containers, trash cans, cement bottles and spreaders,
film band holders, supervisors' desks, and filing cabinets.
The use 6f automatic splicing machines equipped with table tops
obviates the need of separate tables. Such machines are desirable be-
cause of the greater ease and satisfaction that results from using them
and the greater volume of work that can be accomplished with them.
Where manually operated splicing blocks are used, all-metal in-
spection tables and adjustable, form-fitting chairs are recommended.
A standardized rewind for all exchanges is recommended. It is
desirable that all rewinds be equipped with brakes, controlled by the
knee of the operator or by the handle of the right-hand rewind, ar-
ranged so as to stop both rewinds simultaneously when applied.
Mounting flanges should be of standard uniform size so that the
Mar., 1933] EXCHANGE PRACTICE 209
hole in the center of the unmounted reel will always fit the hub of the
flanges.
A desirable title cabinet is one built on the order of a chest of
drawers. Each drawer should be approximately two inches deep,
studded with upright movable pegs on which to insert the titles and
their corresponding tags. This cabinet should be kept in one of the
film vaults.
Leader cabinets should have three compartments for the three
different kinds of leader required for the maintenance of film footage.
The gates or apertures through which the film leader is drawn as
needed should be so built as to prevent fire from passing into the
cabinet. Film band holders may be of any type of wall bracket.
Waste film containers should conform to the code of the National
Board of Fire Underwriters.
Cement bottles should hold no more cement than the amount
required for one day's work, and should be equipped with a metal
spreader built into a metal stopper, the weight of which keeps the
bottle closed.
The supervisor's desk should be made entirely of metal and should
have sufficient drawer capacity for keeping all records when not in use.
Filing cabinets should be made entirely of metal and should have
sufficient capacity for filing continuity sheets, records, etc.
The equipment of the film shipping room should consist of packing
and receiving tables, hand trucks, chairs, waste film containers, tools,
shelves, shipper's desk, filing cabinets, and trash cans.
Packing and receiving tables should be strong and made entirely
of metal. They should not be higher than 30 inches. The shelves
should be sufficiently strong and made entirely of metal, and should
have sufficient capacity for storing all cases of film awaiting shipment
or inspection. Hand trucks should be made entirely of metal and
should be equipped with rubber tires. The shipper's desk and chair
should be made entirely of metal, the former having sufficient drawer
capacity for keeping all records when not in use. Filing cabinets
should be made entirely of metal and should have sufficient capacity
for maintaining a complete file of film record cards, showing the "in
and out" movement of film, and for filing all shipping and receiving
records. Waste film containers should conform to the code of
the National Board of Fire Underwriters, and should be kept in one
of the vaults. Trash cans should be of the usual type, having
tightly fitting lids or covers. Tools of sufficient variety to enable
210 CARE AND DEVELOPMENT OF FILM
the shipper to repair equipment and cases properly should be
available.
(6) Home Office Control. — The practice followed by the film ex-
changes should be controlled by the home ofiices, and should be
made to conform to the procedure adopted by them. The exchange
manager should see that the routine standardized by the home office
is rigidly followed in his exchange by, first: the adoption of the
best routines for the maintenance of film and reporting to the home
offices all particular conditions pertinent to them; and, second, the
thorough and capable following up of the procedure by the home
office, so that the national routine may be emended or altered when
better methods of operation are developed by an individual exchange.
Exchanges should render weekly reports on film inspection. When
reports are compiled, a national summary is obtained, from which
each exchange may be judged as to the volume of work, cost of in-
spection, shipments, and amount of uninspected film in the vaults.
Exchanges should also report all fire hazards at least once a month,
supplementing the monthly report made by the Motion Picture
Producers and Distributors of America. Traveling auditors from
the home office also should include in the audit of each exchange an
accurate and complete description of all fire hazards.
The home office should have available a representative who is
thoroughly informed in film maintenance so that his services might
be furnished to an exchange when needed. The control by the
exchanges of the care of film while in the hands of the projectionist
should include only a correct record of the condition of the print
furnished to the theater and an observation of its condition on its
return. Such records assist in avoiding controversies over damaged
film and charges rendered to the theater by the exchange.
The success of the film exchange in its work depends upon furnish-
ing the exchange with the correct equipment, establishing uniform
standards of routine in all exchanges, and control by the home
office to see that the adopted routine is carried out.
TREVOR FAULKNER, Chairman
W. H. BELTZ AMOS HIATT
A. S. DICKINSON E. D. LEISHMAN
GEORGE EDWARDS J. S. MACLEOD
J. H. SPRAY
FILM RECORDERS5
A. G. ZIMMERMAN**
Summary. — The evolution of the modern high fidelity recorder, from the rela-
tively crude apparatus first used for recording when sound was added to the picture, is
traced; beginning with the telegraphic recording device known as the pallophoto-
phone developed by C. A. Hoxie, passing through the phono film devised byL.de Forest,
and continuing through the RCA PR-1 and PR-3 to the up-to-date PR-4 variable
width recorder embodying the latest developments for maintaining a high constancy
of speed and for producing recordings of the highest quality. The paper describes
the new model recorder and film phonograph, and the application of these to dubbing
and re-recording, both on 35-mm. and 16-mm. film.
From the time that Thomas Edison made the first scratch in the
foil-covered cylinder down to the present day, the words quality or
fidelity have been used in criticism of the recordings that were made,
no matter what method was used. These words define, perhaps, a
condition of pleasantly or satisfactorily exciting the auditory nerves
in a manner bearing a recognizable relation to the original sound.
It is highly probable that with Mr. Edison's first recording, the tre-
mendous impetus that he received from having accomplished what
was heretofore locked in the fastness of the unknown, caused him to
rejoice in the discovery that he had made. It is a historic fact that
Mr. Edison and his co-workers gave some thought at that time to
one feature of recording that in this day and age has become of
paramount importance. This feature was partially obscured by the
fact that he had "re-created," in the form of a permanent or semi-
permanent record, an audible sound that once had been, and could
be no more.
As the art of recording progressed, all the individuals connected
with it came to realize that the attainment of good quality, as regards
the frequency composition of sound, was one of the greatest problems
confronting them. But quality was found to have a wider scope, and
to include a definite relation between the frequency characteristic
and the constancy of speed maintained while recording and reproduc-
* Received February 15, 1933.
** Engineering Department, RCA Victor Co., Camden, N. J.
211
212 A. G. ZIMMERMAN [j. S. M. P. E.
ing the sound. As in all developments of this nature, the past efforts,
when reviewed at some later time, were considered to be poor replicas
of what had been recorded, and served to emphasize the achievements
accomplished during the interim.
The progression from the cylinder to the disk type of record brought
with it considerable advantages, both from the commercial and from
the technical standpoint, when the increase in the linear speed was
considered as well as the creation of a more flexible product. This
advance brought with it a wider field for the sale of records and repro-
ducing machines or phonographs.
Departing from the field of quality with respect to the frequency
standpoint and considering only the question of constancy of speed,*
it is very probable that since the conception of the phonograph down
to the present day, millions of dollars have been spent by firms en-
gaged in the original recording of phonograph records for sale, by
others engaged in marketing reproducing machines, by engineers,
and other individuals too numerous to mention who were privately
interested in solving the problem of speed constancy. Undeniable
strides were made in reducing, to a tolerable limit, the variation of
speed that occurs in recording and reproducing equipment of the
phonograph type.
Mr. C. A. Hoxie, of the General Electric Company, conceived the
idea of a telegraphic recording device that would enable a telegraph
company to receive telegraphic communications at high speed on a
continuous paper film and to preserve them for their records.** As
soon as this device had been created and so improved as to be able to
record messages at speeds previously considered impossible, the
ever alert engineering instincts of the men responsible for this de-
* Inconstancy of speed results in variations usually termed wows when they
have a frequency below 10 cycles per second; flutter up to 50 cycles, and gurgle
above 50 cycles. The frequency of the gurgle is usually dependent upon the
number of sprocket teeth engaging the film.
** A historical point worthy of mention is the fact that the original sensitized
paper film recorder was developed to record the telegraphic signals when trans-
mitted at the usual maximum speed of 25 to 35 words per minute. Concurrently
with the development of the recorder, the possibility of increasing the speed was
apparent, and during the winter of 1918 and 1919 a Hoxie telegraphic recorder
was operated at Otter Cliffs, Bar Harbor, Maine, handling traffic from Lyons,
France, at an average speed of 50 words per minute. Further developments and
tests demonstrated the ability of this type of equipment to receive as many as 250
words per minute.
Mar., 1933] FILM RECORDERS 213
velopment conceived the idea that not only telegraphic messages,
requiring only the comparatively simple dot-dash method of record-
ing, but other sounds, such as the human voice and music, could be
recorded on a piece of film, which could be processed and reproduced.
In 1922, Mr. Hoxie developed what is now known to the industry
as the pallophotophone* which he described in detail at the Mid-
Winter Convention of the A.I.E.E. in New York in 1923.
The success of Mr. Hoxie's trials and demonstrations of the pallo-
photophone immediately created an impression on the minds of
interested persons that the era of talking pictures was definitely at
hand. Dr. Lee de Forest's demonstration of the phonofilm at ap-
proximately the same time also contributed to the advent of the
"talking picture." It is not to be inferred that these two men were
the first to think of ''talking pictures" with the sound recorded on the
film, but credit is due them for their efforts in accomplishing and pre-
senting for commercial development what had heretofore been ac-
complished only in the laboratory or had been conceived but never
accomplished.
The pallophotophone and its uses and demonstrations aroused at-
tention to a requirement that had been of considerable importance to
the record industry previously to this time; namely, the constancy of
speed that should be maintained in recording as well as in reproducing
sound on film.
It was found that when recording sound on a continuous strip
of film, particularly the recording and reproducing of sustained
notes, the least possible variation of speed of the film was required
as it moved past the recording or the reproducing light. These
variations would produce objectionable variations in the reproduced
sound and prevent it from being a faithful replica of the original
sound. It was apparent, then, that with the advent of the talking
picture, suitable equipment for recording sound on film and for re-
producing the sound from the film would be required. Mr. Hoxie
and some of his associates designed and built a film recorder known
at the time as the kinegraphone, later known as the photophone film
recorder. This device, designated the PR-1 Recorder, employed a
* The name pallophotophone has been given to devices used for permanently
recording speech as a wavy trace on a moving photographic film, and for trans-
forming the air vibrations of sound directly into exactly corresponding electrical
vibrations for transmission; for example, to wireless broadcasting generators.
The word is a Greek derivative, signifying "dancing light."
214 A. G. ZIMMERMAN [j. S. M. P. E.
synchronous motor and a train of gears driving two sprockets. As
the film passed through the recorder, it was drawn over a cylindrical
drum, to which a flywheel was attached by means of a shaft. This
drum was isolated from the sprockets, and the sprocket-tooth pulsa-
tions, by means of loops of film threaded around suitable rollers,
although the film was relied upon to drive the drum. Acoustical
power recording methods could no longer be used; the method of
recording on the film, in the PR-1 recorder, was an outgrowth of
Hoxie's work with the telegraphic recorder and other work done in
the laboratories of the General Electric Company on oscillographs
and vibrators. In the field, the PR-1 recorder performed remarkably
well, notwithstanding the obstacles with which it had to cope. It
was the first commercial film recorder to be called upon to withstand
the rebuffs of a slightly unsympathetic film industry, to say nothing
of some rather belligerent directors and directors' staffs. A new era
had dawned in the film world, and the PR-1 took its place in the front
ranks of the invaders.
Recollections are not all that remain of the hectic days during the
nascency of "sound" and its adoption by the already mature and un-
doubtedly independent silent film industry. Much was to be learned
from the conditions prevailing in the studios under which the sound
equipment would have to work. Where laboratory experiments had
sufficed for the original developments, field experience was now to be
had; and in so far as the recorder was concerned, commercial film pre-
sented problems, both chemical and mechanical. Only the me-
chanical difficulty of shrinkage and its relation to the attainment of
constant speed will be discussed. In the PR-1 recorder, the isolating
loops between the sprocket and the film drum were of such a nature
that when a disturbance occurred in the speed of the film during re-
cording, more filtering or damping action was required than the
flywheel alone would furnish. This resulted in an unsteady motion
of the film past the recording light beam.
A new recorder, the PR-3, was developed, in which was employed
a mechanical device to compensate for the shrinkage of the film.
In the PR-3, a synchronous motor was used to drive a flywheel
through a pinion and gear, or a worm gear reduction. On the same
shaft with the flywheel, within the recorder head, a sprocket was
mounted, which pulled the film from the film magazine. A cone on
this shaft was arranged to drive another cone on the recording drum
shaft through the medium of an idler, the position of which was
Mar., 1933]
FILM RECORDERS
215
determined and controlled by means of a compensating roller in the
film path within the recorder head. This mechanism would compen-
sate for shrinkage of the film, causing the speed of the recording drum
to be in accordance with the exact linear dimension of the film. This
compensating mechanism, although a mechanical device, served to
make sound-film very superior to that obtainable with the now ob-
solete PR-1 recorder.
As was to be expected, the device employing the mechanical means
cLTt |
O SPEEP
FIG. 1. Speed-torque curve of the electromag-
netic drive of the PR recorder.
of maintaining a constant film speed in the PR-3 recorder was not
free from mechanical troubles, starting with the friction between the
cone and the idler of the compensating mechanism. Mr. E. W.
Kellogg, of the General Electric Research Laboratories, realizing
the difficulties of the mechanical compensating device, and aware
of the advantages to be gained by isolating the film drum from the
remainder of the operating mechanism, developed in the laboratory a
recorder that employed a magnetically overdriven drum.1 The ad-
vantages of this construction were immediately apparent, and a new
type of recorder was designed and built, in which were incorporated all
the advantages of the earlier recorders as well as the improvements
necessary to overcome the disadvantages or troubles encountered in
216 A. G. ZIMMERMAN [j. S. M. P. E.
manufacturing them and operating them in the field. This recorder
was known to the industry as the PR-4. With this instrument it was
feasible to record on film the sustained notes of the piano, without
being able to detect any variation of frequency when the sounds re-
corded on the film were reproduced. Having accomplished this ob-
jective of maintaining a sufficiently constant speed of the film, it then
became necessary to combine the new features that enabled this to be
FE£D MAQA.7.1NE
EXPOSURE- LAMP
AMMETO2,
FIG. 2. Front view of a model 4PR18A1 35-mm. film recorder showing
threading.
done with other features that were the outgrowth of extensive field ex-
perience.
With the development and manufacture of the PR-4 recorder, the
limitations and other objectionable features of the oscillographic type
of galvanometer were vacated by using a galvanometer of such design
that the moving parts were more readily controllable and the fre-
quency range extended beyond what was reasonably and economically
possible with the oscillographic type of vibrator. After a recorder
Mar., 1933]
FILM RECORDERS
217
embodying this new vibrator had been placed in service in the field,
the advantages of reducing the ground noise of the film record, dur-
ing passages of small amplitude or during quiet intervals, became
apparent. This consideration led to the development of equipment
comprising an amplifier arranged to operate a shutter vane, which
intercepted part of the beam of the recording lamp, so that, when the
amplitude of the sound that was being recorded exceeded a certain
threshold level, the full output of the amplifier would be available.
This arrangement improved the quality of the record considerably,
MAGAZINE CLAI
TAKE -UP MAGAIiNE
PAD V.
MOTO8. 5W!TCH
FIG. 3. Front view of type PR-19 16-mm. film recorder showing threading.
as, by means of it, shots taken without speech or music would be
almost completely "blacked out" on the positive film and neither
scratches nor dust would cause disturbances in the reproduced
sound.
By the time the PR-4 recorder was operating in the field, the public
had whole-heartedly accepted the talking picture, so that in that
respect the metamorphosis of the silent picture was complete. Di-
rectors and associates, including the actors, had come to realize that
the technic of recording sounds on film had changed the old order of
218
A. G. ZIMMERMAN
[J. S. M. P. E.
affairs to such an extent that, with complete cooperation, the art
was considerably advanced.
In order to keep pace with the rapid advances made in the labora-
tories and in the field, where literally thousands of technical men were
developing new equipment or operating the old equipment (on a com-
mercial basis), it was necessary to provide the film industry with new
and improved tools. Consider by what yardstick the new recorders
were to be measured: primarily, as has been shown, the recorder
O TVPt PfV79 P
FIG. 4. Front view of a model 4PB36A1 35-mm. film phonograph.
would be required to record sound on film with the utmost attainable
as regards constancy of speed and range of frequency. The recorder
would have to embody, as well, the attributes of ruggedness, sim-
plicity, flexibility, and durability. High fidelity was, then, to be
realized, at least as far as recording was concerned, in the latest film
recorder available to the film world — the PR-18,
From the point of view of the recorder, we find high fidelity re-
quiring two important features, as before: constancy of speed and
Mar., 1933]
FILM RECORDERS
219
adequate range of frequency. In so far as the speed was concerned,
with the electromagnestically driven recorder drum as used in the
PR-4, constant frequency recordings of continuous frequencies were
assured, without perceptible variations of speed. (It is to be noted
that in making measurements of this kind, the methods used are
rather simple but the work becomes quite fine and would warrant
a detailed description not possible at this time.) A sleeve-bearing
formed the journal for the sound-drum shaft, so it was necessary to
FO-CUSt N<i ADJUSTMEHT, s —35MM $?ePRQOUCH*& £S»TKAt. SYST
\\ „. (..ftfnP ADJUSTMENT CS.RMP
\\\ r — LAMP VeSTtCflL ADJUSTMENT
T ROTATIONAL RSuUSTMEBT-, \\ \ \ r<ju«y>
IfeMM KEC(X20i:'E. OPTICAL
, LATERAL AOJU&TMCNT
/ f EXPOSURE LftMP HOUSI
^QALV^NOMeTt.S?,
\ .SWITCH &RTTEBV
\ . SWITCH
KcMn etcoKope
CONTROL PftMf I
FIG. 5. Front view of type PB-38 35-mm. to 16-mm. film re-recorder showing
threading.
develop a combination of bearing and shaft metals and a lubricant
that would insure minimum friction, minimum bearing noise (me-
chanical), and maximum uninterrupted service. The shaft and
sound-drum of the recorder were made of stainless steel so as to avoid
corrosion. Considerable developmental work had to be done before
the proper combinations were determined and acceptably proved.
From the electrical point of view, although the magnetic drive has
been explained previously, 1 a brief description of it may be in order at
this point. It consists of a solid copper annulus, fixed in a support-
220
A. G. ZIMMERMAN
[J. S. M. P. E.
ing flywheel attached to the drum-shaft. An electromagnet, driven
by the recorder motor through reduction gears, is constructed so that
an annular air-gap is formed on its rear surface. The copper ring,
by reason of its construction, fits into the air-gap and rotates only
when the electromagnet is properly excited by a direct-current source.
Fig. 1 shows a speed-torque curve of the magnetic drive motor.
In this curve, NIi represents the field excitation for a given current;
and TV/2 the excitation for a greater current, producing a proportion-
ately greater flux density in the air-gap. From this figure, it is evi-
FIG. 6.
Front view of a 4PB38A1 35-mm. to 16-mm. re-recorder showing
threading.
dent that for small changes of speed (dS) of the film drum (no matter
what the cause), there will be an opposing or damping action mea-
sured as an increment of torque in accordance with the subtended lines
shown on the vertical scale. It is further evident that the greater
the slope of the curve, the greater will be the damping produced by
the increment of torque dT. The magnet drive in the recorder is
usually designed to drive the magnets at a speed that is approximately
10 per cent greater than the speed of the drum.
An optical system2 capable of responding faithfully to the in-
creased frequency range, and yet simple and rugged enough to be a
Mar., 1933] FILM RECORDERS 221
practical "tool," had to be designed. The optical parts in general
were mounted on a unit casting and designed so as to prevent all
possible variations in their arrangement. The galvanometer was of
a new type, necessitated by the extension of the range of frequency of
the response. It is of the balanced armature type, and employs a
mirror of such dimensions that the "edge to area" ratio is reduced to
a harmless minimum, resulting in a substantial reduction of the stray
light impinging on the film. The stray light is reduced still further
by mounting the window in front of the mirror at an angle, so that
any secondary reflection from it will not impinge upon the mechani-
cal slit. The reduction of the stray light and the increase in the
area of the mirror permit the use of a less sensitive film for a given
current in the exposure lamp.
The operation of the optical system differs from that of all previous
types in that the sound track is recorded by moving a triangular light
image in a vertical direction across a horizontal slit, and optically
reducing the cross-section of the light beam so that the sound track
becomes a serrated pattern on the film, varying from a 0.002-inch line
at the center to the full width of the sound track, on both sides of the
center. The resulting sound negative then becomes two identical
serrated transparent areas, completely separated by an opaque area.
One description given of the sound track is that it resembles "a
mountain chain and its reflection, as mirrored in a body of water at
the foot of a range."
In this optical system, the ground noise is reduced by depressing
the light image (by direct current supplied by the ground noise
reduction amplifier) to such an extent that the tip of the triangular
light image is just incident upon the mechanical slit. This, produces
on the film an opaque track 0.002 inch wide. By means of a bias
winding in the galvanometer, in addition to the modulation winding,
and by using the ground noise reduction amplifier, this depressing ac-
tion is made to occur when no modulation is present in the recording
channel. As soon as modulation occurs, or a modulating signal is
picked up by the microphone, the ground noise reduction amplifier,
by means of a timed circuit, operates and permits the modulation
coil of the galvanometer to vibrate the mirror in accordance with the
incoming alternating-current signal. The mechanical construction
of the galvanometer is extremely simple, and, due to the fact that the
armature is designed so as to become saturated at a predetermined
flux density, the galvanometer is practically self-protecting.
222 A. G. ZIMMERMAN [j. S. M. P. E.
A volume level indicator or "monitor" is mounted on the top rear
surface of the base casting. It consists primarily of a small paper
screen upon which a small portion of the vibrating light beam is
focused. This small portion of the beam is reflected to the screen,
through a window in the cover, by a mirror that intercepts an inde-
pendent beam of light parallel to the recording beam. By drawing
lines on the card and by observing the relative position of the light
beam while recording, it is possible to observe very accurately the
modulation of the sound track.
SOCKET ROTATIONAL
FIG. 7. . Optical system used in type PR- 18 film recorders. Top view with
cover removed.
Having the elements of a successful recorder, namely, the constant-
speed film drive and the optical system, it was then necessary to in-
sure mechanical reliability by mounting all the equipment on a rugged
base. This base was designed to house and protect all the apparatus
incident to the recorder itself, such as the galvanometer transformer,
the lamp control rheostat, and the field rheostat. Connections were
made to the audio and power circuits of the recorder by means of
Twist-Loc receptacles mounted in panels on the rear of the base.
This method of connection avoids permanent wiring of the installa-
tion. Provision was then made for a control panel, whereon the lamp
Mar., 1933]
FILM RECORDERS
223
and field ammeters, the galvanometer, motor, and the battery
switches were mounted.
Thirty-five-mm. recorders of the PR-18 type have been in constant
service for the past seven or eight months, and sound records are being
commercially produced with them of an excellence that heretofore
has been sought after, but never attained.
Having produced such a recorder, embodying all the mechanical
MICROSCOPE
&ARR.EL SHOULDER,
MICBOSCOPE &ARREL
OBJECTIVE CLAMPiNQ
5CCEW- SET IN TH)5
POSITION FOR. FOCUSING
-5ET CLAMPING SCREW
IN THIS POSITION FOE.
FOCU51NQ FILM
PHONOGRAPHS
EYE P1ECE-
O&JECTIVE APERTURES
FIG. 8. Focusing microscope for use with 35-mm. film recorders and
film phonographs.
features that have been mentioned, and having available all of the
attributes necessary to record sound on film at a constant speed, it
was immediately evident that these features could be incorporated
into an equipment capable of reproducing sound with the same
nicety. In order to accomplish this, it was necessary to replace the
optical system of the recorder with a system designed to reproduce
the high fidelity records made with the recorder. Here again, the
224 A. G. ZIMMERMAN [j. s. M. P. E.
requirements of the field demanded that such a system be provided
as would reproduce sound tracks faithfully no matter what type of
record was used or to what extent the recordist had misplaced the
sound track or misaligned the recording slit. The optical system that
was developed includes a high-intensity filament lamp and a mechani-
cal slit 0.0025 inch wide, the latter being optically reduced to a slit
dimension at the film of 0.0005 inch. The optical system is arranged
so that it can be adjusted to the point of critical focus by means of
the focusing microscope. An important feature of the system is the
arrangement by which the entire optical barrel is positively rotated
±2.5 degrees in steps of 0.1 degree. This feature enables the opera-
tor to reproduce sound tracks that have been made either in haste
or when insufficient care was taken in aligning the optical system
FIG. 9. Focusing microscope — component parts.
slit of the recorder. This device has found considerable favor in the
field due to the facility it provides for making the optical adjust-
ments. In speaking of the focusing microscope, the question may
arise as to how it is possible to design a device of this type that can
be made readily available for use in a recorder as well as in a film
phonograph. Fig. 8 shows the assembly of the focusing microscope ;
Fig. 9 shows the component parts, indicating the stop adjustment,
which is set by the operator for the machine with which he is using
the instrument.
With the film phonograph shown in Fig. 4, it can be seen that film
in rolls (kept in this manner to prevent reel marks) can be readily
inserted into the new type of magazine and threaded through the re-
corder head up into the take-up side of the magazine. The reproduc-
ing optical system is arranged so that the light passes through the
film to a photocell mounted in the door of the film phonograph. This
is connected by means of a cable to the phototube amplifier. The
output of this amplifier matches the input of the microphone distribu-
Mar., 1933] FILM RECORDERS 225
tion panel of the standard recording channel. From here, the sound
may be mixed with the output of separate microphones or with the
output of other film phonographs in order to create various sound
effects on the final films.
With a processed film reproduced by the film phonograph, it is
possible to combine two or more sound tracks, to add sound effects to
an original recording, or to match sound levels in the finally edited
picture. The user of the equipment is then enabled to make high
quality re-recordings and dubbings with complete confidence.
Film phonographs are usually furnished with a Selsyn motor
mounted on the base. They are used mostly in re-recording channels,
where the projectors and recorders are operated from a master Selsyn
motor-generator set. The film phonograph is provided with a syn-
chronous motor drive for recording incidental sound effects or for
reproducing "takes" independently in order to check the quality of
recording that has been obtained.
A distinct advantage of the film phonograph as thus designed is
that fresh or "green" film, or rushes, may be run through the machine
without danger of damaging the emulsion by pulling the film through
a sound gate and shoe, because during the course of the film through
the film phonograph head it comes into contact with the surface of
only one roller immediately before it enters upon the sound drum.
This device, like the recorder, is equipped to accept all power
and sound circuits in suitable Twist-Loc connectors mounted on panels
on the rear of the film phonograph base. Also, as in the recorder,
the controls are mounted on a sloping panel directly in front of the
operator. The exciter lamp rheostat is located on the left-hand side
of the base casting within easy reach.
Due to the demand for a recorder capable of recording sound on
16-mm. safety stock with a constancy of speed comparable with that
obtained with nitrate stock at 90 feet per minute, it was evident that
the electromagnetic drive could be applied to such a recorder. With
the idea in mind that the greatest number of recordings on 16-mm.
film would be made by direct re-recording, the recorder was built as
the reverse of the 35-mm. film phonograph. This was done so that
both machines could be mounted on a single base, to be driven by
one motor and the controls and necessary optical systems brought
within easy reach and observation of the operator. The 16-mm.
recorder, although operating at only 36 feet per minute and handling
safety stock with its inherent difficulties, embodies the same features
226 A. G. ZIMMERMAN [j. s. M. p. E.
that are found in the 35-mm. recorder; and in so far as constancy of
speed is concerned, it has not been excelled.
In the development of the 16-mm. recorder, and in order to utilize
the advantages of the magnetic drive, the size of the recording drum
had to be such that it was impossible to use a device similar to the
focusing microscope as used in the recorder and the film phono-
graph. A microscope was therefore mounted in the side of the lens
barrel of the optical system; arranged so that it could be used to
observe the emulsion on the film through the objective lens of the
optical system, and obtain thereby extremely accurate adjustment.
The optical system includes essentially the same components, and the
same arrangement of these components, as a 35-mm. recording optical
system; and monitoring is accomplished in the same manner as in
35-mm. recording, by observing the monitoring light beam as focused
on the monitor screen mounted on the rear of the casting.
Having available the high-quality film phonograph and the 16-mm.
recorder, it was thought advisable to make available, for those inter-
ested in the development of the 16-mm. sound library, a re-recorder
capable of either (a) re-recording from a 35-mm. sound print to a
16-mm. film; (b) reproducing 35-mm. sound film for listening or dub-
bing work; or (c) recording directly on 16-mm. film. It was not
thought economical to make the original recordings on 16-mm. film,
due to the fact that the cost of cutting and editing this film, compared
with that of making direct re-recordings from existing 35-mm. libra-
ries, would be excessive.
The sprockets of the reproducer and the recorder are driven through
reduction gears by a single synchronous motor, thus insuring the
synchronization of the master 35-mm. print with the 16-mm. print,
so that when the picture is printed on the 16-mm. film no difficulties
will be encountered in synchronizing them. The recorder also in-
cludes the feature of housing all the equipment requisite to the re-
producing and recording mechanisms. Controls for the exciter
lamp and the exposure lamp are mounted on either side of the casting
near the front. The motor switch is made common to both the re-
producer and the recorder panels, so that the machine may be oper-
ated from either point or the two units may be operated individually.
The reproducer panel contains the battery switch, the field ammeter,
and the exciter lamp ammeter. The recorder control panel contains
a galvanometer switch, the field ammeter, the battery ammeter, and
the exposure lamp ammeter. All external power and sound circuit
Mar., 1933] FlLM RECORDERS 227
connections are made through the standard Twist-Loc terminals in-
serted in panels at the rear of the base casting.
Briefly, then, the 35-mm. film recorder has progressed from a com-
paratively crude device and utilizing an acoustical method of modulat-
ing the recording light beam into a highly perfected machine in which
is employed a drive that is almost perfect. The equipment includes an
optical system approximately half as large as the earlier system and of
a comparatively simple design. The recording is no longer done
acoustically, but an improved optical system and a galvanometer of
rugged construction are used, capable of recording faithfully a fre-
quency range from 50 cycles to 10,000 cycles. The entire equipment
has been mounted on a base so designed that permanent wiring and
mounting are unnecessary, and all the controls are within the opera-
tor's reach.
REFERENCES
1 KELLOGG, E. W.: "A New Recorder for Variable Area Recording," /. Soc.
Mot. Pict. Eng., XV (Nov., 1930), No. 5, p. 653.
2 DIMMICK, G. L., AND BELAR, H.: "Extension of the Frequency Range of
Film Recording and Reproduction," /. Soc. Mot. Pict. Eng., XIX (Nov., 1932),
No. 5, p. 401.
THE RELATION BETWEEN DIFFUSE AND SPECULAR
DENSITY*
CLIFTON TUTTLE**
Summary. — After briefly referring to the effect of the scattering of light upon
measurements of density, according to the way in which density is measured, the
author alludes to various attempts made in the past to find a quantitative relation
between the specular density and the diffuse density of a medium. A special pro-
jection densitometer was designed for measuring the specular density, and a form of
integrating densitometer for the diffuse density, of a number of samples of negative
and positive motion picture film. The results indicate an exponential relation be-
tween the two kinds of density, the time of development and the variation of gamma,
within the range of the measurements, being negligible.
The influence of the scattering of light by the developed silver grain
upon the effective optical density of a photographic deposit is of
considerable importance to both practical and scientific users of
photographic materials. Density, which is defined as the common
logarithm of the ratio of incident flux to transmitted flux, instead of
being a definite property of the silver image, is dependent upon the
characteristics of the optical system of which it is a part. If the
measuring instrument is so placed as to record only the flux trans-
mitted in a direction normal to the plane of a light-scattering medium,
the density value will be greater than for the case where the measure-
ment is based upon the total transmitted flux. The first case, which
has been termed specular density (d\\), is the value that is of interest
in dealing with images for projection — lantern slides, motion picture
positives, and negatives for enlargement. The second case, which
is usually spoken of as diffuse density (d4f ), is of interest in contact
printing, where the negative and the positive materials are in juxta-
position and the total transmitted radiation is effective.
* Communication No. 258 from the Research Laboratory of the Eastman
Kodak Company. Originally published in /. Opt. Soc. Amer., XII (June, 1926),
pp. 559-565. In a subsequent paper by Silberstein and Tuttle, /. Opt. Soc.
Amer., XIV (May, 1927), pp. 365-373, a formula correlating the two densities
was derived from general theoretical considerations.
** Kodak Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
228
DIFFUSE AND SPECULAR DENSITY
229
The dependence of the density values upon the manner of making
the measurement was the subject of an extended controversy be-
tween Hurter and Driffield and Abney.1 Abney pointed out the
effect due to light scattering. Hurter and DrifHeld agreed with the
FIG. 1. Projection densitometer: A, 900- watt monoplane
filament lamp; B, 5-inch condensing lens; X, photographic
material; C, 41/2-inch projection lens; D, Martens polarization
photometer.
criticism offered by Abney, but stated erroneously that the scatter-
ing interferes only in plates of very high densities. Callier, in his
well known paper on the scattering of light by photographic ma-
terials,2 investigated a number of photographic emulsions, and con-
cluded that the relation between diffuse and specular density was
approximately satisfied by the equation d\\ = Qd-ft, where the factor
FIG. 2. Integrating densitometer: A,
250-watt monoplane filament lamp; B, 12-
inch integrating sphere; X, photographic
material; D, Martens polarization photom-
eter.
Q is a constant for a limited range of densities. Callier 's measure-
ments of diffuse density were made with the photographic material
in contact with opal glass, which was assumed to be perfectly diffus-
ing. Under such conditions, the values he obtained would be true
230 CLIFTON TUTTLE [j. s. M. p. E.
diffuse density values within the range of the densities measured,
since here the effect of interreflection is negligible.
Renwick and Bloch3 have shown that an equation of the exponen-
tial type fits Callier's data with greater accuracy than the linear
function given by Callier.
It has been questioned whether diffuse density measurements give
the true contact printing density. Toy4 found that diffuse density,
when measured by the use of an opal diffuser, must be multiplied
by a constant factor to give the true printing density. Bull and
Cartwright,5 however, found that an integrating-sphere densitometer
gave true contact printing density readings.
The photographic literature is replete with discussions of methods
and instruments for measuring density and with treatments of the
theoretical and practical aspect of the scattering of light by turbid
media. A detailed review and analysis of these papers is beyond the
scope of the present work. Those engaged in photographic research
are probably aware of the uncertainties arising from the use of differ-
ent instruments employing light sources with varying degrees of
collimation. On the other hand, many scientists who make constant
use of the photographic plate as a measuring instrument appear to
be quite unaware of its limitations in this respect. The magnitude
of the difference between diffuse and specular readings in the data
of the following investigation serve to emphasize the necessity for
careful consideration of this property of photographic materials.
It is highly desirable at times to express one density in terms of the
other, i. e., to evaluate contact printing density from measurements
of projection density and vice versa. Such a case arose in connection
with some work on tone reproduction in motion pictures, in which
it was desired to trace the reproduction of original object contrast
through the steps of printing the negative by contact and projecting
the positive on a screen. The measurement of negative printing
density on a projection densitometer designed to measure positive
projection densities simplifies the problem of locating corresponding
negative and positive areas, and eliminates the possible error that
might arise from the use of two different instruments. The purpose
of the work reported here is to establish a relation between diffuse
and specular density for certain photographic materials.
The projection densitometer used was designed to approximate
the optical system used for projecting motion pictures (Fig. 1).
Neither the incident beam nor the measured component is strictly
Mar., 1933]
DIFFUSE AND SPECULAR DENSITY
231
TABLE I
Par Speed Motion Picture Negative
d-H-
d\\
d\\/*#
d - calc.
e
7V r*
0.0641
0.108
1.68
0.0647
+0.94%
0.095
0.110
0.180
1.64
0.113
+2.8
0.146
0.223
0.332
1.49
0.220
—1.3
0.228
0.355
0.509
1.41
0.350
— 1.4
0.307
0.460
0.650
1.41
0.457
—0.66
0.360
0.550
0.770
1.40
0.549
—0.18
0.400
0.640
0.891
1.39
0.644
+0.62
0.450
0.790
1.07
1.36
0.785
—0.64
0.482
1.08
1.44
1.37
1.09
0.92
0.563
1.31
1.75
1.34
1.34
+2.2
0.610
1.58
2.00
1.25
1.55
—1.9
0.646
1.89
2.40
1.27
1.89
+0.0-
0.697
parallel. It is interesting to note, however, that the deviation from
parallelism was so slight that a check of this instrument, m?de with
the bench photometer using collimated light, showed no difference
in density readings.
0-4
0-E
00
I" TO
Par Speed Mo+ion Picf ore Nega+ive
/
/
~?
/
\
/
a
y.
/
T-2
To
/
/
/
To
T-z
0-4-
1-6 Ta o-o o-z
Log Specular DensH-y
FIG. 3. Curve plotted from data of Table I.
232
CLIFTON TUTTLE
[J. S. M. P. E.
TABLE n
Motion Picture Positive
d-H- d\\ d\\/d-{\- d-H-calc.
e
Ts/Tt
0.0484
0
.0697
L.44 0.0483
—0.21%
0.046
0.105
0
.152 ]
L.44 0.108
+2.8
0.096
0.230
0
.316 ]
L.37 0.231
+0.43
0.180
0.385
0
.523 ]
L.36 0.390
+ 1.3
0.267
0.438
0
.590 ]
L.34 0.442
+0.91
0.288
0.485
0
.651 ]
L.34 0.489
+0.82
0.310
0.565
0
.761
.35 0.575
+ 1-7
0.343
0.689
0
.902
.31 0.686
—0.44
0.391
0.770
1
.01
.32 0.771
+0.13
0.423
0.956
1
.23
.29 0.946
—1.1
0.477
0.982
1
.27
.29 0.978
—0.41
0.493
1.50
1
.95 1.30 1.52
+1.3
0.620
A form of integrating densitometer (Fig. 2) was chosen to make
the so-called "diffuse density" measurements, because from its nature
it actually measured the total transmitted light. This instrument
makes use of the same Martens polarization photometer mounted
02
0-0
Te
a
1-
I
T-2
To
IB
Z«
Mof ion Picture. Posif luc.
x
/
y
/
,
>
/
7
/
/
A
i
0 ~\Z 1-4- 16 T-8 0-0 0-Z
Log Specular Density
FIG. 4. Curve plotted from data of Table II.
Mar., 1933]
DIFFUSE AND SPECULAR DENSITY
233
TABLE III
Eastman 40
rf-tf
d\\
<*ll/d4f
d-H- calc.
e
T,/Tt
0.0650
0.101
1.55
0.0631
—2.9%
0.084
0.113
0.175
1.55
0.155
+1.7
0.125
0.230
0.332
1.44
0.231
+0.43
0.208
0.553
0.740
1.34
0.553
0.0
0.350
0.940
1.23
1.31
0.964
+2.6
0.459
1.11
1.40
1.26
1.11
0.0
0.486
1.24
1.53
1.23
1.22
—1.6
0.510
1.35
1.61
1.19
1.29
+4.6
0.520
1.41
1.75
1.24
1.41
0.0
0.531
1.65
1.95
1.18
1.59
—3.6
0.564
in the same supporting unit as is used with the projection densitome-
ter. The essential difference between the two instruments is in the
measurement of transmitted flux.
A number of densities ranging from 0.05 to 2.00 were prepared
and measured on both instruments. Tables I, II, and III give the
average of five readings for each density. Column 3 gives the ratio
-
T-a
Easfman 40
To Tz 1-4- 1-fe 1-8 oo o-z
Log Specular Density
FIG. 5. Curve plotted from data of Table III.
234 CLIFTON TUTTLE [j. s. M. p. E.
of specular to diffuse density — the Callier Q-factor. Evidently a
linear relation will not satisfy the data. The variation of Q is about
thirty per cent. The data seem to be very much more applicable to
an exponential equation, such as was suggested by Renwick and
Bloch (loc. cit.).
Figs. 3, 4, and 5 show the data of Tables I, II, and III plotted loga-
rithmically. A straight line represents the locus of log d||/log d-\\-,
with a maximum error less than the error of measurement.
The equation of these curves is of the form,
log d-\\- = m log d 1 1 — c
or J4f = d
where m is the slope and c the intercept.
The values of these constants for the three emulsions investigated
are as follows:
m Antilog c
Par Speed Motion Picture Neg. 1 . 088 1.37
Motion Picture Positive 1 . 036 1.31
Eastman 40 1.091 1.30
The values of d-\\- as calculated from d\\ by the formula are given
in column 4 (Tables I, II, and III), and the difference of percentage
(e) between the observed and calculated values in column 5.
A number of samples of motion picture negative emulsion were
developed for different times, the gamma (the slope of the Hurter
and Driffield characteristic curve) being varied from 0.4 to 1.0 in
order to determine the effect of the development upon the ratio of
the specular to the diffuse density. It was concluded that the effect
within this range was negligible. Three sets of motion picture nega-
tive densities representing three different batches of the same kind
of emulsion were tested, and the results were in very good agreement.
It is doubtful, however, whether the constants m and c will hold
with equal accuracy for all batches of the same emulsion, since the
average grain size differs slightly from batch to batch.
In column 5 of Tables I, II, and III is given the ratio of the
scattered transmitted light to the total transmitted light as deter-
mined from the density values. The increase of this ratio is prac-
tically constant with respect to decreasing transmission values from
100 to 30 per cent.
The relation of the scatter ratio to the density is not linear even
for low values of density, as was observed by Eggert and Archenhold,6
Mar., 1933] DIFFUSE AND SPECULAR DENSITY 235
and therefore is not linearly proportional to the mass of the scattering
material present. It is possible that the scatter ratio may be some
function of the perimeter of the interstices between the silver particles,
and it is hoped that by the use of single grain layers, some such cor-
relation may be found.
REFERENCES
1 HURTER, F., AND DRiFFiELD, V. C.i "Photo- Chemical Investigations and
a New Method of Determination of the Sensitiveness of Photographic Plates,"
J. Soc. Chem. Industry (May, 1890), p. 455.
ABNEY, W. M. W.: "On the Accuracy of the Grease Spot Photometer for
Measuring the Density of Photographic Plates and a Note on the Sector Photom-
eter," /. Soc. Chem. Industry (July, 1890), p. 722.
HURTER, F., AND DRIFFIELD, V. C.: "Reply to the Preceding Communi-
cation of Captain Abney," etc., J. Soc. Chem. Industry (July, 1890), p. 725.
2 CALLIER, A.: "The Absorption and Scatter of Light by Photographic
Negatives, Measured by Means of the Martens Polarisation Photometer,"
Phot. J., 49 (1909), p. 200.
3 BLOCK, O., AND RENWICK, F. F.: "The Opacity of Diffusing Media,"
Phot. J., 40 (1916), p. 49.
4 BULL, A. J., AND CARTWRIGHT, H. M.: "An Evaluation of the Light Scat-
tered by Photographic Densities," Phot. /., 49 (1925), pp. 125, 177.
5 CARTWRIGHT, H. W.: "The Measurement of Photographic Density,"
Phot. J., 48 (1924), p. 180.
6 EGGERT, J., AND ARCHENHOLD, G.: "Das optische Streiwermogen photo-
graphisch entwickelter Silberschiehten," Zeit. fur Physik Chemis, 110 (1924),
p. 497.
MODEL MAKING WITH SHEET FILM BASE
K. HICKMAN AND D. E. HYNDMAN
Summary. — The paper describes methods of using sheet film base in making
models for experimental processes. Methods of cutting and scraping the material
are described at length, as also the manner of making and using the requisite thick
and thin cements employed in making welds. Various illustrations are given in
order to exemplify the processes.
Experimenters in the time of Newton or Priestley were proud to
boast that, from a jam jar, some string, and a piece of sealing wax,
they could construct most of their physical apparatus.
Nowadays, although our laboratories are supplied with a variety of
intricate devices and pieces of glassware, many problems demand
the construction of special apparatus. The methods at our disposal
vary with our constructive skill, but rarely embrace more than
carpentering, glass blowing, soldering and sheet metal working,
plumbing, and elementary electric wiring.
Of these, with the advent of Pyrex, it may be said that glass work-
ing is probably the most useful, and the least dispensable. To be
able to see what is happening inside the apparatus is the great ad-
vantage, outweighing a hundred minor drawbacks. If metal working
could produce transparent articles, the value of soldering and plumb-
ing would be greatly enhanced, and many experimental problems
would be simplified. This article does not describe such a miracle,
but it does compromise by showing how transparent cellulose com-
pounds may be built into useful laboratory apparatus.
Transparent cellulosic sheeting is generally made from cellulose
nitrate or cellulose acetate. The more usual nitrate material is
commonly known as celluloid. Since, however, this is a trade name
for a special product, we shall speak of the material as nitrate base
or sheet; and refer to cellulose acetate sheeting as acetate base.
A word as to the properties of these two substances: nitrate sheet
* Communication No. 370 from the Kodak Research Laboratories. Revised
from the original article published in /. Franklin Institute, 207 (Feb., 1929),
pp. 231-244.
236
MODEL MAKING WITH FILM BASE 237
is a mixture of cellulose nitrates plasticized with camphor. It is
not only inflammable, but it also decomposes in the absence of air.
Decomposition begins between 140° and 170°C., and ignition
occurs at a higher temperature. Below the boiling point of water it
softens sufficiently for molding.
Acetate base, on the other hand, since it contains no camphor,
is not so plastic or easily molded. It can be bent at a temperature
of 100 °C., and will retain its new shape when thus bent. It does not
decompose spontaneously in the absence of air at temperatures be-
low its ignition point, and it does not burn with special vigor. Hence
its use for safety cinematograph film and home motion pictures.
Both materials are softened by certain organic solvents, and two
pieces may be stuck together by placing a drop of solvent between
them and squeezing them into intimate contact. The solvent softens
and partially dissolves the surfaces, and is then absorbed by the mass
of the material as water is absorbed by gelatin. Later it evaporates.
The process, however, can produce a good autogenous weld of a
strength nearly equal to that of the original material.
Nitrate and acetate bases may be bent and welded into compli-
cated shapes. Since they may be stuck to glass, elaborate apparatus
may be built up of dimensions difficult to obtain with glass tubes
alone. Examples will be described later.
Besides the inability to resist heat, neither material will with-
stand strong liquids. The vague term "strong liquids" may be
applied to the following:
Nitrate Base Acetate Base
Concentrated nitric acid Moderately concentrated acids
Concentrated hydrochloric acid 2 per cent alkali
Concentrated sulfuric acid Acetone
10 per cent or stronger caustic alkali Alcohol
Acetone Ether
Alcohol Amyl acetate
Amyl acetate
Both bases will withstand water, solutions of metallic salts, dilute
acids, carbonates, benzene, chloroform, and xylene. Nitrate base
will resist 20 per cent sulfuric acid indefinitely.
CONSTRUCTION WITH NITRATE BASE
The operations involved in working with nitrate base are four in
number, and are extremely simple.
238 K. HICKMAN AND D. E. HYNDMAN [J. S. M. P. E.
They are
(1) Cutting
(2) Shaping
(3) Welding:
(a) to like material,
(6) to glass and other substances
(4) Laminating
Directions given below for nitrate base serve, in practically every
instance, for acetate base.
(1) Cutting. — Nitrate sheet that is to be cemented perpendicularly
to the surface of a second piece (Fig. 1) should never be cut. The
scissors should be reserved for trimming the edges of finished articles.
No matter how carefully the cut is made, the edge will deviate slightly
from a straight line or pure curve. A convenient way to part ni-
trate or acetate sheeting is to draw a sharp point, in pencil fashion,
along a straight edge. A "Moore" glass push-pin works well, and
may be discarded when the point is blunt. Old razor blades are not
suitable because they tend to depart from the marked line. When
a good clean scratch has been made, the material is bent until,
with a slight snap, it parts along the entire length. Circles are cut
with the dividers, placing a piece of scrap sheet under the center
leg so as to avoid making a large pivot hole. Two or three revolu-
tions with the dividers leaning in the direction of travel will make a
deep enough scratch. If the internal circle is to be used, two or
three scratches are ruled tangentially to the circumference, and the
outer portion is broken away. When it is the outer ring that is
wanted, the inner circle must be detached by carefully applying
pressure with the thumbs. It is better to work the material back-
ward and forward than to apply excessive force.
Other shapes are easy to produce. An ellipse is made by guiding
the cutting point with a loop of string held between two fixed pivots.
Wavy contours are produced with French curves. The line is first
built up with a grease pencil from various positions of the curve and
is then retraced, still using the curve, with the sharp point.
(2) Shaping. — The many cellulose nitrate articles available com-
mercially are evidence that with molds and dies any shape can be
produced. Molds are not common in the laboratory, so that the
shaping operation is generally limited to simple bending. Varia-
tions of the cube and the cylinder are practicable, but not of the
sphere.
Mar., 1933] MODEL MAKING WITH FlLM BASE 239
Three kinds of equipment are requisite for bending: a square
metal bar, a selection of metal rods, and a vessel of hot water. The
metal bar is perhaps the most useful.
The inflammable nature of nitrate base would suggest using hollow
bars and tubes that could be warmed with steam from an electric
kettle. We have found it safe, however, to use a Bunsen burner,
making sure that the sheeting and cement are pushed out of the way.
The bar has available four edges and four sides. At least one
edge should be rounded, forming part of a circle of about Yie-mch
radius (Fig. 2). All four sides may be at right angles, or the bar
may be a right-angled triangle. In this case the other two angles
should be rounded as well. The bar is used to supply heat to the
sheet, and no matter how sharp a bend is desired, there should be
sufficient bearing surface to convey the heat.
The bar is warmed by waving the Bunsen flame along its length
until the moistened finger just sizzles when touching the upper
surface. The flame is now extinguished, and the sheet brought into
contact with the bar. A line should previously have been ruled
with the grease pencil where the bend is to be made. On no account
should a scratch have been made. The ends of the sheet are grasped
in the two hands, and when it has begun to yield, the regions near
the bend should be pressed with wood strips, or smothered tightly
with a cloth. When the desired angle has been attained, the sample
is removed, taking care to maintain the angle until the material be-
comes cold (Fig. 3). The procedure is similar when making a less
sharp bend around a rod.
Sometimes it is necessary to produce an irregular shape to fit some
special contour. In Fig. 4 the pieces a-a' are similar and have two
edges at right angles, while the third follows the special contour;
a and a' form the side pieces to the angular strip c. Let us suppose
it is necessary to bend b so that it may be cemented in place to com-
plete the box. b is cut to a strip x/4 inch wider than called for, and
at least an inch longer. Placing the piece a beside a bowl of water
hotter than the hands can bear, b is held with pliers and immersed.
In a minute it is withdrawn and given a quick pressure with the hands
at V (Fig. 4a), and allowed to spring away again. It will have taken
a slightly permanent shape. If it does not match the curve of a
sufficiently, the warming and pressing are repeated until a slightly
exaggerated bend is attained. The curves at W, X, Y, and Z now
receive attention, exaggerating each one, in order, a little less than
240 K. HICKMAN AND D. E. HYNDMAN [J. S. M. p. E.
its predecessor. In this way the final sample is found to have curves
at the right places, but owing to its recovery in warm water, each
curve is a little less pronounced than needed. This is an advantage,
for when fixture is made at the point T (Fig. 4a), pressure at 5 brings
the whole strip into contact with a and allows the cementing to be
accomplished in one operation.
(3) Welding, (a) Autogenous: Base to Base. — The require-
ments are thin cement, and thick cement, in suitable containers, and
some hog's hair brushes, in holders from which the varnish has been
scraped. The containers are easily made from 16-ounce wide necked
bottles supplied with large corks that do not fit too tightly. Through
a central hole in each cork a stout walled test tube, 3/4 inch in diameter
and 6 inches long, is pushed from below. This is much better than
having the brush itself fixed in the cork (Fig. 5) .
Many formulas for film cement have been published, but since
only small quantities are needed, we have found it convenient to use
the ready-made Eastman cement without inquiring into its composi-
tion. This is the thin cement referred to above.
The thick variety is made by dissolving scrap base, cut into strips
an inch and a half long by Vie-inch wide, in the thin cement. A
spare bottle is filled one-third full of the chips and cement is poured
in until the bottle is more than half filled. The mixture is stirred
vigorosly with a stout glass rod every ten minutes throughout the
day and left to settle overnight. In the morning the clear thick
syrup is decanted into the container from a slight residue of gelatinized
strips. A brush is selected, placed in the syrup, and the cork thrust
home.
It should be understood at the outset that nitrate sheet sticks to
itself by virtue of its own powers of adherence. The cement is used
merely to prepare the surfaces. After these have momentarily been
flooded, the best joins are obtained when the surfaces are pressed
together tightly enough to extrude every trace of unabsorbed liquid.
Obviously, the thick cement will not be pressed out as efficiently as
the thin, and will therefore not make as good a join. The thick
fluid should therefore be used for external reinforcement of the join.
Joins are of two kinds, perpendicular and parallel, or end to face
and face to face. The latter is lamination on a small scale.
The parallel join is very easy to make. One sample is stood at
an angle on the other, and a few drops of cement from a pipette or a
brush are laid in position. The upper sample is quickly laid down
Mar., 1933] MODEL MAKING WITH FlLM BASE 241
and an even pressure applied all over with the flat of the hand or a
cloth pad. A piece of blotting paper placed underneath will absorb
the excess cement pressed from the edges. The operations are shown
in Figs. 6 and 7, while the finished join is being tested in Fig. 8.
The perpendicular join is more difficult but is much more useful.
At its simplest, the straight edge of a piece of base is pressed tightly
against the surface of another piece, while a little thin cement is run
along the angle at each side (Fig. 9) . The pressure is maintained for
30 seconds after all trace of liquid has disappeared, and the sample
left undisturbed for an hour. It is then held in an inclined position
(Fig. 10), while a drop of thin cement is placed at the top of the angle
on each side and allowed to run down, which it should do quickly.
Immediately a big drop of thick cement is placed in the same posi-
tion and allowed to fall slowly along each crevice. At every inch or
two of fall it should be replenished, not at the top, but at the head
of the traveling drop. Finally the sample is put away to dry for one
day on a level surface, after which a section of the join should present
the appearance in Fig. 11. The object of the pre- wetting with thin
cement is to prevent the inclusion of air bubbles.
If the thick cement had been applied to the corner with a brush,
it would have formed ridges where they were least needed, yielding
a finished product like Fig. 12.
The reinforcing cement must be used with caution. It sets after
partially drying into the shape of the join, but later when more
solvent has evaporated it contracts and pulls the pieces into a more
acute angle than was intended. The reinforcing should always be
done on two sides of the join and sometimes, if the appearance of
Fig. 13 is to be avoided, on three. The properly finished join is
shown in Fig. 11.
Most perpendicular joins are less simple. They are the kind in-
volved when an end, a side, or a partition is cemented to a shaped
container. Fitting a circular disk into the end of a cylinder is per-
haps the simplest case. The disk, cut to fit tightly, is pushed into
place and thin cement is run all round. Since there is no tendency
for the join to come apart, the thick cement may follow immediately.
A large globule is placed in one crevice, and the cylinder is rotated
until the syrup has fallen all around. The other side is then treated.
Fastening the end into a rectangular box is a little more difficult.
The sides of the box may be completed before or after insertion of
the end. In the first case, the end piece is cut accurately to size, but
242
K. HlCKMAN AND D. E. HYNDMAN [J. S. M. P. E.
the corners are rounded off more than would appear necessary. It is
thrust into position and cement applied at the center of the long sides,
holding them against the end piece for at least a couple of minutes.
The centers of the short sides next receive treatment, and cement is
finally brushed all around. One hour should elapse before the ap-
plication of the thick cement.
FIGS. 1-13, INCLUSIVE. Illustrating the manner of making the various kinds of
joins.
Mar., 1933]
MODEL MAKING WITH FILM BASE
243
When the rectangular box is to be built around the end piece,
it should be fitted by trial and error before any cementing is done.
The join is most conveniently made in the middle of a long side.
FIGS. 14-21, INCLUSIVE. Illustrating the procedure of making more complicated
constructions.
244 K. HICKMAN AND D. E. HYNDMAN [J. S. M. p. E.
Cementing of the top plate is begun with one-half of the split long
side (Fig. 14), being careful that the plate is pushed snugly up to
the corner. After a few minutes, the other sides may be brought into
position and secured. Finally the free half of the split side, previously
given a rebate by pressing between two thin metal plates in a vise
(Fig. 14&), is cemented in place and a parallel joint made all the
way down The simplest way of all of closing the rectangle is to stand
it on a plate larger than actually required, run cement all around
the crack, and follow this, within and without, by thick cement
(Fig. 15).
(4) Lamination. — Although joining sheet to glass and other
materials is next in order for consideration, it will be convenient first
to describe lamination. If two thin sheets be placed face to face,
with their ends between the rollers of a horizontal mangle (Fig.
16), cement may be poured into the junction and they may then be
rolled into one homogeneous piece. In place of a mangle one may use
a drawing board and a gelatin composition roller of the kind favored
by printers for inking up halftone blocks (Fig. 17). With a ten-inch
roller pieces 9 by 20 inches may be built up with ease. One sheet
11 by 25 inches is laid on the board. A thin line of cement drops is
placed at one end, and a second sheet secured above it along this
edge. Holding the upper sheet at an angle of 45 degree, a liberal
pool of cement is poured into the angle, after which the roller is
pushed smoothly but quickly forward. Enough cement must be
used to stick the entire length. It is convenient to squirt the liquid
from the original can.
Laminating is a messy operation. The cement exudes from sides
and end and is very likely to get on the board or under the clean
bottom face of the nitrate base. This may be prevented by doing
the operation on blotting paper. It is important that the freshly
laminated material should have the uncemented side portions cut
away at once. It should be allowed to hang vertically for some hours,
because any bend suffered at this stage will impose a permanent
curvature.
Nitrate base is readily obtained in thicknesses of 5, 10, and 20
thousandths of an inch. The 20-thousandths sheet is the most use-
ful, and by laminating two or three thicknesses, a sheet sturdy
enough for most requirements can be made.
The need is soon encountered for nitrate tubing. Unfortunately,
we have been unable to obtain this in lots of less than 50 pounds,
Mar., 1933]
MODEL MAKING WITH FILM BASE
245
and have been forced to make it by lamination, or else press glass
tubing in service. Short lengths can be made very simply after the
manner shown in Figs. 18 and 18a. Cement must not get between
the pyroxylin and the glass, otherwise the mandrel can not be with-
drawn.
(3b) Welding Nitrate Base to Other Materials, — The base does
not make good shafts or bearings, or good narrow tubes. When-
ever moving parts are involved, or fluids have to be conveyed to
containers, glass or metal spindles or tubes have to be affixed to the
sheeting.
Nitrate base cemented to smooth glass or metal adheres fairly
well until one corner becomes lifted. Then any slight strain strips
FIG. 22. Transparent crystal model.
it away. This happens particularly easily under water. Conse-
quently the base and glass (or metal) have to be so shaped that the
one surrounds the other completely and without the possibility of
rotation.
Cementing a Glass Tube into a Nitrate Container. — Two methods
have been used successfully. In the first, the glass is indented in
the blow pipe flame and when cold a chip of base is thrust into the
cavity. A thick tube is then laminated over this, wetting the glass
with much cement. When the walls are a quarter of an inch thick,
the whole assembly is cemented to the side of the vessel. Fig. 19
shows the procedure in detail.
The other method involves an unsymmetrical expansion in the glass
so as to make the grip secure. A flat uneven bulb is blown, and a
number of washers are cut to fit its contours, the outer ones just
246 K. HICKMAN AND D. E. HYNDMAN [j. S. M. P. E.
fitting the undistorted tube. These are cemented in position one
by one, giving the effect shown in Fig. 20. Such built up collars make
extremely strong joins. Shafts may be pushed through nitrate
Pelton wheels, or film developing drums, and secured at each contact
by some modification of the procedure. Good contact can often be
made between a glass tube and a single plate of the rotor by merely
denting the glass at the junction and painting it liberally with thick
cement. This dries into the hollow and produces firm adhesion.
Steel and copper offer no especial difficulties except that the cement
must on no account contain acetic or other acid.
A device that has proved useful is shown in Fig. 21. A spiral of
FIG. 23. Model of film developing drum.
narrow nitrate tube was wanted. Accordingly, a coil of fine copper
piping, having an outside diameter equal to the internal diameter
of the finished tube, was wound into a well-spaced spiral and sup-
ported by a wire handle. It was then dipped about 30 times into
thick nitrate cement, allowing at least three hours for drying between
successive dips. The dipping required rigid adherence to a certain
sequence of operations. First, the spiral was dipped with a slanting
motion into thin cement and quickly withdrawn. It was then
instantly lowered slowly in a slanting manner into the thick cement.
When under the surface it was rotated through 180 degrees and
removed at an angle, being careful that each convolution left the sur-
face without forming a drop. Once out in the air, it was rotated in
all directions for a minute or two until the new layer had set. It
was then hung up to dry.
Mar., 1933]
MODEL MAKING WITH FILM BASE
247
After the thirtieth coat, it was dried for a day in the 60°C. oven.
The copper spiral was then dissolved out with 1 : 1 nitric acid. This
was a tedious operation, owing to the driving of the acid out of the
spiral by the gases formed. It has to be done quickly or degrada-
tion of the nitrate base sets in. Finally, when the copper was entirely
removed, a mixture of water with 25 per cent industrial alcohol was
drawn through, a few cc. per minute, for a day. The spiral, when
FIG. 24. Complex model of industrial instrument.
dried, served its purpose sufficiently well. One is shown, minus
the copper core, at the right of Fig. 21.
Strength and Rigidity. — Thin nitrate sheet is too flexible to be
mechanically rigid unless it is bent and secured in many directions.
A careful design will include sufficient cross pieces. When these
are not admissible, right-angle struts and bracings may be put across
the straight sides. They will be observed in some of the later
figures.
Tinting. — Both nitrate and acetate base may be colored by dyes
dissolved in a mixture of alcohol and acetone. The particular mix-
248 K. HICKMAN AND D. E. HYNDMAN
ture of solvents must be found to suit the individual worker. Gen-
erally speaking, the more acetone, the more strongly the color will
take.
Sphere of Usefulness. — In the laboratory we have found the
construction described here useful for making :
Models of crystals and atoms, where it is desired to see top, bottom,
and contents, all at the same time (Fig. 22) .
Film developing drums, for use in those photographic researches
where it is inadvisable to let the developer touch anything but glass
and film substance (Fig. 23) .
Containers in hydraulic systems, where it is necessary to observe
the path taken by the water.
Certain industrial instruments, where the solutions attack metals
(Fig. 24).
A more ambitious use is found in the construction of architects'
models, and for the building of miniature movie sets. The architect
has, in the past, been content to build his miniatures from pasteboard
which, though excellent for exteriors, gives the patron little idea of
the internal lay-out. It is possible to build cottages or even towns
from nitrate or acetate stock, and show a superior external surface
and a full view of the interior arrangements.
A Word of Caution. — Acetate sheeting is generally a trifle less
transparent and less easy to work than nitrate sheeting. It is to be
preferred, however, for all large construction work because of its
safety. Both materials shrink with age, the contraction being
most marked at the joints. The less liberally the solvent or cement
is applied during construction, the less serious will be the distortion.
Simple pieces of apparatus may have a life of years, but heavy
cemented pieces of unusual shape are likely to present a distorted
appearance at the end of a few months.
THE DEPICTING OF MOTION PRIOR TO THE ADVENT OF
THE SCREEN
EARL THEISEN*
Summary. — The motion picture as it is known today has existed less than fifty
years but certain of the principles which underlie its development can be traced
back many years more. This paper represents an attempt to list chronologically
the chief devices and inventions pre-dating the motion picture equipment of 1895.
25,000 B.C. — The earliest known example of motion expressed
pictorially was found in a cave at Altamira, Spain, representing a
trotting bear having two sets of legs, probably an attempt to repre-
sent the one set of legs in two different positions ; the relic was found
in rocks of the Upper Paleolithic period, and probably was the work
of a Cro-Magnon.1
5000 B.C. et seq— Ombres Chinois, "Chinese Shadow Shows." All
races have evolved shadow shows, indicating the general thought to
represent motion pictorially. Records exist of shadow shows in
Egypt and India before the time of Christ. Historical records indi-
cate that in Java shadow shows were included in every festival.
The shadow shows, termed wajang, employed miniature figures
grotesquely made of leather, cardboard, wood, or other mate-
rials, the shows revolving about the Javanese customs and myths,
gods and devils. The operator, or gamelong, manipulates the figures
before a fire, so as to throw the shadows of the figures upon a screen,
accompanying the movements with suitable conversation and music
furnished by reeds and gongs. The audience, squatted before the
screen, views a realistic representation of the conflicts between gods
and devils.
In France, in 1767, Seraphim presented shadow shows by
means of a magic lantern. The series was popularly known as
Chinese Shadow Shows, or Ombres Chinois. Caran d'Ache de-
veloped these shows further, establishing them as French Shows, and
presented historical tableaus. Color was introduced by Henri
* Honorary Curator, Motion Picture Collections, Los Angeles Museum, Los
Angeles Calif.
249
250 EARL THEISEN [j. s. M. p. E.
Riviere by adding colored bits to the figures; he tried also to arrange
the figures so as to provide perspective in the shadows by using two
lanterns so arranged as to present dissolving views. 2>3>4>6
65 B.C. — Titus Lucretius Cams6 in De Rerum Natura wrote as
follows :
"Do not thou moreover wonder that the images appear to move,
And appear in one order and time their legs and arms to use.
For one disappears, and instead of it appears another,
Arranged in another way, and now appears each gesture to alter,
For you must understand that this takes place in the quickest time."
This is probably the earliest recorded discussion of pictorially
represented motion. From this record it would seem that some
kind of device for depicting motion existed at that time.
130 A.D. — A record of this date of a device for depicting motion
exists in the Bodleian Library, Oxford.7
1640 A.D. — About this time the Magia Catoptrica, also known as
the Megaloscope, was invented by Athanasius Kircher. This device
was a lantern, similar to the present-day magic lantern, with which
were projected drawings. A favorite subject for projection was a
drawing of the devil with his trident. Kircher wrote a book entitled
Ars Magna Lucis et Umbrae (Great Art of Light and Shadow) in 1646. l
1806. — Henry L. Child's invention of the Phantasmagoria, or
Bi- Unial Lantern, was announced about this time. The device was
used to entertain audiences nightly at the Sanspareil Theater, London,
now known as the Adelphi. Subsequently there appeared a great
number of magic lanterns and slide-shows of hand-drawn trans-
parencies.
1824 (Dec. 9). — Peter Mark Roget read before the Royal Society
in London a paper describing the principle of persistence of vision,
using for illustration a revolving and progressing wheel, the spokes
of which could be seen through a vertical aperture placed in front of
the wheel.8
1826. — The Thaumatrope was invented about this time by John
Ayrton Paris.9 This device was similar to one made several months
before by Dr. W. H. Fitton at the suggestion of Sir John Herschel.10
It consisted of a cardboard disk with two strings attached to the
edges. One side showed the picture of a bird, the other side a picture
of a bird-cage. Upon spinning the disk, the bird appeared to the
onlookers as though it were in the cage. This is said to be the first
device that depended for its operation upon the persistence of vision.
Mar., 1933] MOTION PICTURE CHRONOLOGY 251
1831. — The physical and visual phenomena of motion were studied
by Michael Faraday, in England, by means of a series of geared
wheels, one combination being known as "Faraday's Wheel."11
1831. — The Phenakisioscope, later known as the Phantascope, was
invented by Joseph Antoine Ferdinand Plateau.12 This device was
composed of two disks revolving together on a single shaft ; one disk
had a series of slits around its periphery, the other a series of drawings,
in phases, of a complete movement or action. When the disks, con-
taining the slits and drawings, were revolved, the appearance of
motion was obtained by looking through successive slits as they
passed a given point. Plateau, in Belgium in 1843, lost his sight as
a result of his experiments in vision.
1832. — A Stroboscopic Device was invented by Dr. Simon Ritter
von Stampfer, in Austria, which was identical with Plateau's device,
although Plateau and von Stampfer worked independently of each
other.
1834. — The Daedaleum, or Wheel of the Devil, was invented by
William George Horner, of England. This device was a slitted
cylinder, mounted on a stand, through the slits of which could be
seen drawings mounted within.
1850. — Perret and Lacroix improved the Phantascope by adding
to it a front-slotted disk, the first to be used.
1853. — Kircher's magic lantern and von Stampfer's motion device
were combined into a single instrument by Lieut. Baron Franz von
Uchatius, for the purpose of showing the trajectory of bullets; this
was the first time that pictures showing motion were projected.
1860. — The Zootrope, or Wheel of Life, was patented in France by
Desvignes. This device should probably be regarded as the fore-
runner of the motion picture due to its great popularity at this time.
Galloping horses formed the favorite subject for exhibition.13
1861. — Dumont patented in England a device for exhibiting
motion that consisted of a series of photographs arranged as facets on
a prismatic drum made of glass.14
1861 (Feb. 5).— Coleman Sellers patented in the United States the
Kinematoscope.™ Photographs of his children were made in suc-
cessive phases of action by means of a camera having two lenses, the
photographs thus being stereoscopic; these photographs were then
mounted seriatim on the blades of a paddle, and were viewed through
a stereoscope while moving away from the viewer as the paddle was
turned by hand. Action was thus built up during the exposure pose
252 EARL THEISEN [j. s. M. p. E.
by pose; the wet plates were kept moist with glycerin between
poses, dry plates having not yet been invented. In the name of this
instrument the word kinema was used for the first time in connection
with pictures of moving objects.
1864 (Apr. 25). — Louis Arthur Ducos du Hauron was granted a
French patent on a device operating on the principle of persistence
of vision.
1865. — In France, Omnius and Martin photographed the beating
heart of an animal, recording the beats in diagrammatic form.
1866. — J. A. R. Rudge succeeded in photographing successive
phases of motion; exhibiting in 1868 the scenes so taken with his
Bio-Phantascope, or lantern. Two of the mechanisms, notably a
shutter and an intermittent movement used by him in the design of
this lantern projector, are similar in principle to those employed later
by others in connection with motion picture apparatus. Rudge, in
1885, became associated with Friese-Greene.
1866. — Beale invented the Choreutoscope.1
1867 (Apr. 23). — A patent was granted to William Lincoln in the
United States on a device known as the Zootrope, similar to Desvignes'
device.16'17
1869. — Linnet patented his Kineograph, a device in the form of a
book, for showing pictures of moving objects. The principle of this
device was employed in the Biograph Company's Mutoscope.
1869. — Trevor patented a system of taking radial photographs
rapidly on glass.
1870 (Feb. 5). — The Phasmatrope, invented by Henry Renno
Heyl, was exhibited on this date at the Academy of Music at Phila-
delphia. It was a device having pictures on glass, mounted radially
on a wheel, which pictures were exposed successively and intermit-
tently to the rays of a lantern by a cam and pawl mechanism. The
instrument embodied many of the principles of the present-day pro-
jector. As his first subject Heyl chose a pair of dancers waltzing,
the results being exhibited at the Academy to an audience of 1600
persons.18
1871. — Thomas Ross announced his Wheel of Life.
1872. — At Leland Stanford University, Eadweard Muybridge
produced photographs of trotting horses, using five cameras placed
side by side. The culmination of his experimental work occurred in
collaboration with John D. Isaacs.19
1874. — Janssen developed the photographic pistol, employing a
Mar., 1933] MOTION PICTURE CHRONOLOGY 253
single lens and one plate ; it was used for astronomical purposes only,
particularly for taking pictures of the planet Venus in its successive
phases.20
1876. — A device for tripping cameras, somewhat similar in
arrangement to the electrical door-bell, was developed by John D.
Isaacs, working in conjunction with Muybridge. In this device was
used a shutter patented in England in 1856 by Thomas Skaife. The
number of cameras used for photographing the trotting horses was
increased from five to twelve, then finally to twenty-four. These
cameras faced a white background forty feet long. As the cameras
were side by side, the horses would appear, when the pictures were
projected, as though they were kicking past the background.18
1877. — Emile Reynaud devised the Praxinoscope, for projecting
upon a screen pictures drawn on a continuous band of a substance
called crystalloid. The first subject so produced was Poor Pierrot,
which was first exhibited at the ' 'Reynaud Electrical Theater."
Reynaud also developed a device similar to the Zootrope, with a
central drum of faceted mirrors.21
1877. — Jean Louis Messonier made transparencies of Muy-
bridge's horse-pictures, which were mounted on a glass disk rotating
before a slotted opaque disk and illuminated by a lantern. This
device was known as the Zoopraxoscope.
1882. — Dr. E. J. Marey developed the photographic gun. This
device registered on a glass plate 12 successive pictures of white fig-
ures against a black background at a speed of 1/2ooth second for
each picture.20- 22> 23
1882. — Van Hoevenbergh was granted a patent on a card-
flipping device.24
1885. — William Friese-Greene exhibited pictures of successive
phases of motion, photographed by the Marey method on a single
glass plate. In 1888 he began to experiment with transparent
sensitive paper; and in 1889, applied jointly with Mortimer Evans
for a British patent, using conceptional drawings, from which the
apparatus was later constructed. He was also granted a British
patent25 on stereo-motion pictures in 1893, and a color patent26 in
1898.1'27'28
1886 (Nov.). — Louis A. A. Le Prince applied for an American pat-
ent on a camera having sixteen lenses or less (specification calls for six-
teen lenses). On Jan. 10, 1888, a patent29 was granted, eliminating
claims on one- and two-lens cameras because of the interference of
254 EARL THEISEN [j. s. M. P. E.
Dumont's British patent14 of 1861. On Nov. 16, 1888, a British
patent was granted to Le Prince on a single- and multiple-lens
camera and projector, using the Geneva movement. Although the
Le Prince camera was never exploited, Le Prince experimented with
sensitized paper and gelatin bands for film until the fall of 1889,
when he is said to have obtained sensitized celluloid.30
1887. — Edison, assisted by W. K. L. Dickson, began his experi-
ments with motion devices. In August, 1889, he obtained a short
length of sensitized Tollable film on a nitrocellulose base from George
Eastman.31 The Kinetoscope, employing a non-intermittent move-
ment, was demonstrated at West Orange, N. J., on Oct. 6, 1889. A
patent32 was applied for on a camera in August, 1891, and granted in
August, 1897. The peep-show Kinetoscope began its commercial ex-
hibits at 1155 Broadway, New York, N. Y., on April 14, 1894, at the
Holland Brothers' Peep-Show Parlor. In April, 1896, Edison acquired
the Jenkins-Armat and Armat projector patents, constructed a projec-
tor, and began exhibits at Koster and Bial's Music Hall during the
week of April 23, 1896. The Projecting Kinetoscope was made in 1897.
The Edison camera of 1889 was capable of photographing forty
pictures per second.33 Edison's choice of the picture size and film
width as well as four perforations to a frame are considered by many
to have established these standards for the industry which later
developed so rapidly.
1888 (June 13). — Wallace Goold Levinson read a paper before
the Brooklyn Academy of Photography, describing his invention, a
wheel with photographic plates moving in sequence.
1889. — Anchiitz devised the electrical tachyscope, a large wheel
having pictures drawn about the rim.1
1893-4. — Exhibitions are claimed to have been given in Washing-
ton, D. C., by C. F. Jenkins, using a projector designed by himself
and called the Phantoscope** Mr. Jenkins is said to have begun
experimenting in 1890 on cameras for photographing pictures in
rapid succession and to have devised several with single- as well as
multiple-lens systems. In 1893, he built the Phantoscope* which
used a beater movement.35 On March 25, 1894, he entered into
* The Photographic Times (1894) contains a picture of the Phantoscope camera
and a series of pictures made with it. Also the following "... the pictures are
reproduced in an optical lantern upon any size screen, so rapidly that the eye
does not see the pictures except as one continuous picture with the objects ap-
parently in motion."
Mar., 1933] MOTION PICTURE CHRONOLOGY 255
partnership with T. Armat for the purpose of constructing, exhibiting,
and promoting the device. Models were constructed and taken to
the Cotton States Exhibition in Atlanta, Georgia, in October, 1895.
1894 (Feb. 5). — Two Kinetoscope films were projected by J. A.
LeRoy before a group of about 25 persons assembled in H. Riley's
Optical Shop, 16 Beekman St., New York. The projector used was
designed and built by Mr. LeRoy who had previously (1893) built a
projector which handled unperf orated film.36
1894 (Nov.). — Herman Casler obtained a patent37 on a card-
flipping device. Pictures of successive phases of motion were mounted
on a geared hub. Several other patents were granted to Casler: on
a sliding device that flipped pictures of successive phases of motion,
Nov., 1895 ;38 on a hand-shaken device with mounted pictures;39 and
in May, 1897, on a device40 similar to Coleman Sellers' Kinemato-
graph (1861), although Casler's device was not stereoscopic. In
February, Casler obtained a patent41 for the Mutoscope. The
Casler patents were used by the American Biograph Company in
their peep-show devices, as were the W. K. L. Dickson patents of
September, 1897.42
The American Biograph Company, formed by H. N. Marvin,
W. K. L. Dickson, E. B. Koopman, and Herman Casler, gave an ex-
hibit with the Mutoscope, using a screen, at Hammerstein's Olympia
Music Hall on Oct. 12, 1896. The Mutoscope contained a roller
mechanism that intermittently squeezed the film to move it for-
ward, then perforated the film while it was at rest, for the printing
operation. Litigation later proved the Biograph friction move-
ment to be the only one that did not infringe on the Edison and
Edison-Armat patents.43'44'45'46'47 Illustrations of the friction device
known as the web feeding device and the Biograph apparatus as a
whole can be found in the itemized patent specifications.
1895 (Mar. 22). — Louis and August Lumiere publicly demonstrated
their Cinemawgraphe on Mar. 22, 1895. A public exhibition, for
which an admission fee was charged, took place at the Grand Cafe in
Paris on Dec. 28, 1895. Using a planetary cam movement, the
pictures were projected to a screen. The Lumieres obtained celluloid
from the United States and sensitized it. Their camera photo-
graphed sixteen pictures per second.18
1895 (Apr. 21).— Woodville Latham with the assistance of E. A.
Lauste completed the Pantoptikon, later known as the Eidoloscope.
On Apr. 21, 1895, the first press exhibit of pictures projected to a
256 EARL THEISEN [j. s. M. P. E.
screen by this continuous-movement device was given at 35 Frank-
fort Street, New York, N. Y. On May 20, 1895, commercial exhibits
began in a storeroom at 153 Broadway, New York. The patent
specification48 applied for June 1, 1896, lists a loop device later known
as the Latham Loop. This patent was declared invalid in litigation,
later, due to a prior reduction to practice by Thomas Armat.49'50
1895 (Sept.). — Thomas Armat, continuing his experiments inde-
pendently of C. F. Jenkins, completed the Vitascope projector, later
commercially manufactured by Thomas A. Edison, after Edison had
acquired from Armat certain patents on the Geneva star movement51
and beater movement.52 The first public exhibition of the Vitascope
took place at Koster and Bial's Music Hall, April 23, 1896.53
1895 (Oct.).— The Robert Paul projector was perfected, with the
assistance of Birt Acres.18 A demonstration was held at the Royal
Institute, London, on Feb. 28, 1896. The first experiments con-
cerned continuous movements, but finally the seven-point Maltese
Cross was incorporated in the mechanism and successful exhibits
were held.
REFERENCES
1 DAY, W. E. I.: "Illustrated Catalog of the Will Day Historical Collection
of Cinematograph and Moving Picture Equipment," London, 1930.
2 La Nature, No. 777, France (Apr., 1888), pp. 521, 522.
3 RAFFLES, THOMAS S.: "History of Java," Vol. I, John Murray, London
(1817), pp. 336, 338.
4 ZIEGLER, FRANCIS J.: "Puppets, Ancient and Modern," Harper's News
Monthly 96, (1896) p. 85.
5 "Parlour Magic — Chinese Shadow Shows," 5th ed., W. Kent & Co., London,
(1861), pp. 56, 58.
6 CARUS, TITUS LUCRETIUS: De Rerum Natura.
7 Martin Duncan's Lecture (Nov. 22, 1905), Society of Arts, London.
8 ROGET, PETER MARK: "Explanation of an Optical Deception in the Appear-
ance of the Spokes of a Wheel Seen Through Vertical Apertures," Phil. Trans.
Royal Society, 115 (1825), pp. 131-40.
9 PARIS, J. A.: "Philosophy in Sport Made Science in Earnest," 3 vols.,
London (1827). Copies in collection of W. Day. See Ref. 1.
10 BABBAGE, CHAS.: "Passages from the Life of a Philosopher," London, 1864.
Copy in collection of W. Day. See Ref. 1.
11 FARADAY, M.: "On a Peculiar Class of Optical Deception," /. Royal In-
stitution, 1 (N. S.) (1831), p. 205.
12 PLATEAU, J. A. F.: "Lettre sur une Illusion d'Optique," Ann. de Chimie
et de Phys. (2) XLVHI (1831), p. 281.
13 MATHEWS, BRANDER: "The Forerunner of the Movies," Century, 87 (Old
Series) or 65 (N. S.), April, 1914, p. 916.
14 Brit. Pat. 1457.
Mar., 1933] MOTION PICTURE CHRONOLOGY 257
16 U. S. Pat. 31,357.
16 U. S. Pat. 64,117.
17 Luxz, E. G.: "Animated Cartoons," Chas. Scribner's Sons, New York, 1920,
p. 29.
18 RAMSAYE, TERRY: "A Million and One Nights," Vol. I, Simon & Schuster,
New York, 1926, p. 18.
19 MUYBRIDGE, EADWEARD: "Horse in Motion," University of Pennsylvania,
1882.
20 Cassell's Encyclopedia of Photography, 14th Ed., 1912.
21 "Le Theatre Optique," La Nature, Part 2, France, 1892, p. 127.
22 TALBOT, F. A.: "Moving Pictures," Lippincott Co., Philadelphia, Pa., 1912,
pp. 13, 18.
23 MAREY, J.: "La Chronophotographie," Gauthier-Villars, Paris, 1899.
24 U. S. Pat. 259,950.
25 Brit. Pat. 22,954.
26 Brit. Pat. 21,649.
27 Motion Picture News, XII, Aug. 11, 1911.
28 "A Machine Camera Taking Ten Photographs a Second," Scientific Ameri-
can, Supp., XXIX (Apr. 19, 1890), No. 746, p. 11,921.
29 U. S. Pat. 376,247.
30 SCOTT, E. K.: "Career of L. A. A. Le Prince," /. Soc. Mot. Pict. Eng.,
XVH (July, 1931), p. 46.
31 ACKERMAN, C. W.: "George Eastman," Houghton Mifflin Co., New York,
1930, p. 277.
32 U. S. Pat. 589,168.
33 DICKSON, W. K. L.: "History of the Kinetograph," A. Bunn, New York,
1895.
34 RICHARDSON, F. H.: "What Happened in the Beginning," Trans. Soc. Mot.
Pict. Eng. (1925), No. 22, p. 63.
35 JENKINS, C. F.: "Animated Pictures," H. L. McQtieen, Washington, D. C.,
1898, pp. 26-44. U. S. Pats. 536,569 and 560,800; also "Chronophotography,"
The Photographic Times, 25 (July 6, 1894), p. 2.
36 CRAWFORD, M.: "J. A. LeRoy — Projection Pioneer," J. Soc. Mot. Pict.
Eng., XVI (Jan., 1931), No. 1, p. 109.
37 U. S. Pat. 549,309.
38 U. S. Pat. 584,305.
39 U. S. Pat. 614,367.
40 U. S. Pat. 597,795.
41 U. S. Pat. 652,796.
42 U. S. Pats. 636,500 and 636,642, Sept., 1897.
43 U. S. Pats. 611,590 and 611,591; Patent Gazette, No. 84, p. 2006.
44 U. S. Pat. 636,717, May 9, 1899; U. S. Pat. 636,715, Mar. 11, 1899.
45 "The Court Decision in Patent Case," The Bill Board, XIX (Mar. 16, 1907),
No. 17, pp. 56, 140.
40 Motion Picture News (Feb. 15, 1913), p. 685.
47 "The Art of Moving Pictures," Scientific American, LXXVI (Apr. 17, 1897),
No. 17.
48 U. S. Pat. 707,934.
258 EARL THEISEN
49 New York Sun, Apr. 21, 1895.
50 HOPWOOD, HENRY V.: "Living Pictures," Optician and Phot. Trades Review,
London, 1899; also 2nd ed., The Hatton Press, London, 1915.
" U. S. Pat. 578,185.
" U. S. Pat. 673,992, Feb. 19, 1896.
53 Morning Times, Washington, D. C., Oct. 14, 1896.
BIBLIOGRAPHY OF GENERAL REFERENCES
"La Chronophotographie," by L. GASTINE, Gauthier-Villars, Paris, 1897.
"Picture Ribbons," by C F. JENKINS. Published by C. F. Jenkins, Washing-
ton, D. C., 1897.
"Animated Pictures," by C. F. JENKINS. Published by C. F. Jenkins, Wash-
ington, D. C., 1898.
"La Photographic Animee," by E. TRUTAT, Gauthier-Villars, Paris, 1899.
"La Chronophotographie," by J. MAREY, Gauthier-Villars, Paris, 1899.
"Living Pictures," by H. V. HOPWOOD, Optician and Photographic Trades
Review, London, 1899. Contains an excellent review of early patent literature.
(Revised 1912 and 1915.)
"Die Kinematographie," by K. W. WOLF-CZAPEK, Union Deutsche Verlags.,
Dresden, 1908.
"Motion Picture Work," by D. S. HULFISH, American School of Correspondence,
Chicago, 1913.
"Wissenschaftliche Kinematographie," by F. P. LIESEGANG, E. Liesegang,
Diisseldorf, 1920.
"Moving Pictures — How They Are Made and Worked," by F. A. TALBOT,
Lippincott Co., Philadelphia, 1923.
"Histoire du Cinematographe," by G. M. COISSAC, Gauthier-Villars, Paris
1925.
"A Million and One Nights— The History of the Motion Picture," by T.
RAMSAYE, 2 vols., Simon & Schuster, New York, 1926.
"Geschichte der Kinematographie," by WILHELM DOST, W. Knappe, Halle,
1925.
"The Will Day Historical Collection of Cinematograph and Moving Picture
Equipment." Book of Sales dated Jan. 21, 1930. Solicitors, Bulcraig & Davis,
London.
"A History of the Movies," by B. B. HAMPTON, Covici-Friede, New York,
1931.
THE HISTORY OF NITROCELLULOSE AS A FILM BASE
EARL THEISEN!
Summary. — The following chronology deals with the evolution of motion pictures
as produced photographically on a nitrocellulose support carrying a light-sensitive
emulsion of one kind or another. Even though the later dates of the preceding chro-
nology overlap the earlier dates of the one that follows, the two chronologies have been
kept distinct in order to present the history of the nitrocellulose film base as a unit in
itself.
•
1845-6. — The discovery of the cellulose nitrates about this time is
credited to Schoenbein, who became associated with Bottger some-
time subsequently to August, 1846. 1>2
1847. — The solubility of the cellulose nitrates, especially in alcohol
and ether, was accurately investigated by Gladstone; these experi-
ments no doubt led to the subsequent discovery of collodion.1
1848. — Iodized collodion was used by Frederick Archer Scott in his
calotype wet-plate process.3
1855. — Alexander Parkes was granted an English patent on parke-
sine, a substance similar to collodion, made by mixing anhydrous
wood alcohol with guncotton.4
1868. — Daniel Spill invented xylonite, a combination of pyroxylind,
alcohol, and ether; he was associated with Parkes in some of his
work.5
1869.— John W. Hyatt, of Newark, N. J., invented celluloid by
combining collodion with camphor, for which he was granted a
U. S. patent6'7 on June 15, 1869; in the patent specifications the name
pyroxylin was used. Numerous patents were granted to the Hyatt
brothers covering various uses of this material as artificial ivory.
The name celluloid first appeared in the U. S. Patent Gazette
on July 2, 1872, in the name of the Celluloid Manufacturing
Company, of Albany, N. Y., assignee of the various Hyatt pat-
ents. 8>9'10
* Honorary Curator, Motion Picture Collections, Los Angeles Museum,
Los Angeles, Calif.
259
260 EARL THEISEN [J. S. M. p. E.
1876. — On November 9 of this year, an English patent11 was issued
to Wordsworth Donisthorpe on the Kinesograph, a device to be used
for taking photographs on glass plates arranged as a pack, each plate
dropping out of the way of the succeeding plate after being exposed.
Pictures were taken at the rate of eight a second. The patent
specified that the pictures were to be finished on paper and spaced
equidistantly thereon. Another patent was granted to Donisthorpe
on August 15, 1889, specifying the use of an electric spark for pro-
viding intermittent illumination in a viewing device. In La Nature12
appears the following description of Donisthorpe's work: "If the
apparatus be arranged to take the successive pictures at sufficiently
short intervals of time they may be printed at equal distances upon a
continuous strip of paper; this paper, with the whole series of pic-
tures upon it, may be used in the instrument known as the Zootrope
or Phenakistoscope. . . this strip may be wound on a cylinder, to
be unwound from it at a uniform speed to another cylinder, and so
carried on past the eye of the observer, any ordinary means being
used for insuring that the picture shall be exposed only momentarily
to the observer. By this means the movements made by a person
or group of persons, or any other object during the time they were
being photographed, may be reproduced to the eye of the observer."13
1884.— W. H. Walker and George Eastman, on June 27, 1884,
assigned to the Eastman Dry Plate & Film Company a patent
application on the process of coating paper with an emulsion having
a soluble under-coating so that it might be applied to a stripping
process; granted in 1890. 14
1887. — Hannibal Goodwin, in May of this year, applied for a U. S.
patent on a method of preparing a celluloid support for photographic
emulsions, the title being "Photographic Pellicle and Method for
Producing Same." The patent15 was granted on September 13,
1898; it is said that Goodwin did not reduce it to practice. This
patent was later the subject of lengthy litigation, which was ulti-
mately decided in favor of Goodwin's successors.16'17
1888. — John Carbutt, in Philadelphia, began the commercial
manufacture of films coated on sheet celluloid, obtained from a
company in Newark, N. J. He apparently experimented with this
product for two or three years before he could make it commercially.18'19
1888. — Wallace Gould Levinson on June 26 applied for a U. S.
patent,20 which was subsequently granted, describing further de-
velopments along these lines.
Mar., 1933] MOTION PICTURE CHRONOLOGY 261
1889. — On April 9, Harry M. Reichenbach applied for a U. S. pat-
ent, which was granted on December 10, on a method of making
transparent sheets of celluloid; a mixture of methyl alcohol, camphor,
nitrocellulose, amyl acetate, and fusel oil was dried on a polished
support, after which it was stripped off and coated with the photo-
graphic emulsion. This patent was assigned to the Eastman Dry
Plate Company. The apparatus for coating the film base was pat-
ented by Eastman on March 22, 1892. 21 According to present
records, the first supply of this stock to be used for producing suc-
cessful motion pictures was sent to W. K. L. Dickson at the Edison
Laboratories in July or August, 1889. 18> 22
1891. — Eastman daylight-loading roll introduced.
1895. — In August, Eastman introduced the first positive motion
picture stock; prior to this time motion pictures were made on nega-
tive film, which could be bought in 100-foot lengths. Many experi-
menters in Europe at this time bought the Eastman uncoated nitro-
cellulose film bare and coated it themselves, notably the Lumiere
brothers in France.
1903. — Eastman introduced film having a gelatin coating on the
rear surface in order to counteract curling of the film; the process
had been patented by him in 1890.
1904. — W. C. Parkin, in France, was granted a patent23 on a method
of making celluloid non-inflammable by adding a soluble metallic salt to
ordinary celluloid. Subsequently, many others, chiefly in France, were
granted patents on various ways of rendering celluloid non-inflammable
or slow-burning, by means of adding various metallic salts.24
1913. — In September, Eastman introduced panchromatic negative
motion picture film.
1919. — Eastman, introduced for the first time film that had latent
image footage numbers printed on its edge; the markings included
also the date, which was later omitted, and the markings evolved into
the form as used today. The system was patented by Joseph Aller
in 1922, the application being made in 1917.
1921. — On March 1, Eastman introduced colored base positive raw
stock in nine colors: orange, amber, light amber, yellow, pink, red,
green, blue, lavender, in addition to clear (black and white). Prior
to this time, colored stock had been made in the various finishing
laboratories by dyeing the emulsion after the processing of the picture.
1923. — In January Eastman introduced the 16-mm. reversal film
and apparatus for amateur use.
262 EARL THEISEN
REFERENCES
1 WORDEN, E. C.: "Nitrocellulose Industry," D. Van Nostrand Co., New York,
1911, Vol. I, pp. 22-24.
2 International Encyclopedia, 2nd ed., Vol. IV, Dodd, Meade & Co., New York,
1920, p. 753; Encyclopedia Britannica, 14th ed., Vol. 5, 1929, p. 97; Encyclopedia
Americana, 1932 ed., Vol. 6, p. 175.
3 The Chemist, 1851.
4 WORDEN, E. C.: "Nitrocellulose Industry," D. Van Nostrand Co., New York,
1911, Vol. II, p. 568.
6 Ibid., p. 571.
6 U. S. Pat. 88,634.
7 U. S. Pat. 91,341. Method of Making Solid Collodion.
8 U. S. Pat. 91,233. Process and Apparatus for Manufacturing Pyroxyline.
9 U. S. Pat. 133,229, Nov. 19, 1872.
10 WORDEN, E. C.: "Nitrocellulose Industry," D. Van Nostrand Co., New York,
1911, Vol. II, pp. 576-582.
11 Brit. Pat. 4344, Nov. 9, 1876.
12 La Nature, Jan. 24, 1878.
13 JENKINS, C. F.: "Animated Pictures," H, L. McQueen, Washington, D. C.,
1898, pp. 26-44.
14 U. S. Pat. 420,130.
15 U. S. Pat. 610,861.
16 ACKERMAN, C. W.: "George Eastman," Houghton Mifflin Co., New York,
1930.
17 WORDEN, E. C.": Nitrocellulose Industry," D. Van Nostrand Co., New York,
1911, Vol. II, p. 846.
18 British Journal Photographic Almanac, 1926, p. 480.
19 Philadelphia Photographer, 25 (Nov. 3, 1888), p. 672.
20 U. S. Pat. 578,249.
21 U. S. Pat. 471,469.
22 RAMSAYE, TERRY: "A Million and One Nights," 2 vols., Simon & Schuster,
New York, 1926.
23 French Pat. 344,501.
24 BOCKMANN, FRIEDRICH: "Celluloid, Its Raw Materials, Manufacture,
Properties, and Uses," translated from the 3rd German ed., by H. B. Stocks;
Scott & Co., London, 1921.
BIBLIOGRAPHY OF GENERAL REFERENCES
SANFORD, P. G. : "Celluloid," 2nd ed., Crosby, Lockwood & Son, London, 1906.
CROSS, C. F.: "Cellulose," Longmans Green & Co., London, 1901.
NEBLETTE, C. B.: "Photography, Its Principles and Practice," D. Van
Nostrand Co., New York, 1927.
WORDEN, E. C.: "Nitrocellulose Industry," 2 vols., D. Van Nostrand Co.,
New York, 1911.
EARLY STAGES OF KINEMATO GRAPH Y:
C. H. BOTHAMLEY
Summary. — The author, who presided over the meeting of the Photographic Con-
vention of the United Kingdom at Chester, England, in 1890, describes some of
the work of E. J. Marey, Muybridge, Friese-Greene, and Le Prince, pioneers in the
art of producing and exhibiting motion pictures. The information given in this
paper is particularly interesting in view of the personal acquaintance of the author
with these pioneers during the time in which they were conducting their work.
When an invention or development in pure or applied science
rapidly receives recognition and wide application, especially if it be
of a kind that achieves popularity, there is always a chance that the
merits of the pioneers responsible for the invention or development
will be underestimated, and even that the precise part that they
played will be forgotten. For example, though the name of E. J.
Marey, Professor in the College of France, is occasionally mentioned,
it is doubtful whether the importance of his work is fully appreciated,
notwithstanding the fact that his book, Le Mouvement, was translated
into English by Dr. Eric Prichard, and published in 1895. It is not
improbable that this is due to the fact that Marey restricted himself
to his original line of work, the study of the movements of living
things, from the scientific rather than from a popular point of view,
and his book is a somewhat technical account of his results, with
illustrations that are numerous, but on a small scale.
Marey himself states that the real originator of this line of work
was the famous astronomer, Janssen, who, in December, 1874, took a
series of successive photographs of the transit of the planet Venus
across the face of the sun. A rotating circular plate was used, the
interval between successive exposures being seventy seconds. Jans-
sen, moreover, suggested that this method of making successive photo-
graphs at regular intervals might be applied to the study of the motion
of animals, especially of locomotion.
After Janssen, came Eadweard Muybridge who, about the year
1880, or a little earlier, at the suggestion of a Mr. Stanford, a former
* Reprinted from the Photographic Red Book, London (1931), p. 78.
263
264 C. H. BOTHAMLEY [J. S. M. P. E.
Governor of California, applied the principle to the photographic
study of the movements of the horse, and who subsequently ex-
tended his experiments to other animals and to human beings. As is
well known, Muybridge's method was to use a long line of cameras,
the lenses of which pointed across a defined track, along which the
object moved, the successive exposures being made by permitting
the moving body itself to operate a simple system of shutter releases.
The method was cumbersome, being limited somewhat severely by
the number of exposures possible, but the results were very striking
and valuable. A selection of them can be seen in Muybridge's book
in the Library of the Royal Photographic Society. Much new light
was thrown on the mechanics of walking and other movements.
Muybridge was able to demonstrate his results by means of the
projection lantern and, in 1889, gave lectures at Newcastle-on-Tyne
and at other places in the north of England. Professor A. Smithells,
F.R.S., then professor of chemistry in the Yorkshire College (now
Leeds University), persuaded him to come to Leeds and give a demon-
stration of his results. I met Muybridge on that occasion, and was
able to give him some help in setting up his lantern and other equip-
ment. The plates carrying the successive images were fixed to a
large glass disk, which rotated between the condenser and the lens,
while an opaque disk with transparent slits in it rotated in the
opposite direction. The results surprised as much as they delighted
the large and somewhat critical audience before which they were
shown. Perhaps the most striking of all the demonstrations was
that of the wing motion of a large white bird (a cockatoo, I think).
As the wing moved in the up-stroke, brilliantly lighted by sunshine,
we saw most distinctly every plume of tlie wing turn on its base, so
as to present only its edge in the direction of motion, and thus offer as
little resistance to the air as possible. As the wing came down, each
plume turned back so as to present its flat surface to the air and thus
gain the maximum impulse. I well remember the murmur of as-
tonishment and pleasure that went through the whole audience, and
the persistent demands for the repetition of what was as beautiful a
picture as I have ever seen on a screen.
Marey and Muybridge were early in communication, and in order
to obtain simpler and more portable apparatus, Marey invented his
" photographic" gun. This apparatus, it should be noted, required
only one lens. It was built in the form of an ordinary sporting gun,
but of course, with different relative dimensions of its parts, and was
Mar., 1933] EARLY STAGES OF KlNEMATOGRAPHY 265
used on the shoulder and sighted in the same way as a gun. At first,
plates were used, which were attached to a disk of glass contained in a
drum fixed to the gun just as a revolver barrel would be. The disk
could be rotated by clockwork actuated by the gun-trigger. The ex-
posure was first made; then the shutter closed, and the disk moved
around and brought another plate into position. With this ap-
paratus, the number of exposures possible was 12 per second, and the
plates were necessarily very small. Soon, "a continuous film very
slightly coated with gelatin and bromide of silver" was substituted
for plates, the film being wound on bobbins, at the end of which were
flat plates having perforations that were engaged by a peg in a metal
plate in order to rotate the bobbin. Black paper attached to the
ends of the film made filling and changing possible in daylight.
The images obtained with this apparatus were 9 centimeters wide.
The improved apparatus and the increased sensitivity of the films ob-
tainable made it possible to study the movements of a wide variety
of living beings, the results of which study are set out in the book to
which I have already referred.
In a delightful place in Beaune, bounded on one side by one of the
great bastions of the fortifications, and on the other by a row of those
dignified renaissance houses that give a distinct cachet to this quaint
old town, there is a railed-in enclosure planted with graceful trees;
in their midst is a life-sized statue of Marey, a sturdy thick-set
seated figure with a face of marked character. Against the figure is a
mass of stone, on the body of which are carved representations of his
pictures of horses; while, as a frieze, there is a representation of his
study of a flying bird. A long inscription sets out the achievements
and honors of this distinguished Professor of the College of France,
and the esteem in which he was held by his townsmen and country-
men.
Friese-Greene, on June 26, 1890, at a meeting of the Photographic
Convention of the United Kingdom at Chester, over which I presided
as president for the year, read a paper on A Magazine Camera and
Lantern. He exhibited and described the camera that he had in-
vented for making a long series of successive exposures on a sensitive
film, which was moved by means of perforations in the film itself,
instead of by perforations on a bobbin. He likewise exhibited and
described a lantern that he had devised for projecting the images so
obtained. Unfortunately, on the journey from London, the projec-
tion apparatus had been damaged so that it could not be used, and
266 C. H. BOTHAMLEY
the films that Greene had brought with him for exhibition could
not be projected. This accident and the non-descriptive title which
he gave to his paper were most unfortunate, and I am inclined to
doubt whether any of the numerous experienced photographers at the
meeting quite realized what a distinct advance Greene had really
made.
It is a point of interest that the art now so widely applied for
purposes of entertainment originated from a desire for making
scientific investigations, of which most of the patrons of the cinema are
probably ignorant; although to a very limited extent it is occasionally
brought to their notice that the methods used to produce the pictures
that amuse them are still constantly employed in scientific studies of
great importance from various points of view.
Le Prince, whose claims as one of the pioneers I have recently ad-
vanced, I knew well by sight ; in fact, I met him once or twice at the
house of Mr. and Mrs. Wilson, with whom he had gone abroad just
before his mysterious disappearance. I have, however, no recollec-
tion of having heard anything about his work in kinematography up
to the time when I left Leeds in August, 1891, although I was a fairly
regular attendant at the meetings of the Leeds Photographic Society.
Probably he did not desire publicity until he had made satisfactory
arrangements for working his patents.
BOOK REVIEW
Making Better Movies. A. L. GALE AND R. C. HOLSLAG. Amateur Cinema
League, Inc., New York, N. Y., 1932, 205 pp. ; a limited edition for distribution to
members of the League.
The purpose of the book is to unravel some of the mysteries that motion pic-
tures seem to hold for many amateurs, particularly those who are new at the
work, and to discuss the problems of "making better movies." For that reason,
it is written in a rather elementary manner; and although the book might be of
questionable value to professional motion picture engineers, it should be of inter-
est to those engineers, at least, whose commercial activities bring them into contact
with the amateur and the amateur market, so that they may be fully cognizant
of the problems facing the purchasers and users of their equipment and material.
Necessarily, the book deals with 16-mm. film and equipment, a few allusions
being made to the 8-mm. systems. The nature of the book can best be appre-
ciated by considering its contents : Chapter 1 contains an introduction to the sub-
ject, instructions on how to handle the camera, a discussion of sizes of film, expos-
ing, stop numbers, lighting, planning the picture, footage, etc. The second
chapter deals with handling the projector, caring for the film, editing, making
splices, and titles. The third chapter discusses lenses, artificial lighting, subjects
for photographing; and the fourth chapter deals with fades, multiple exposures,
irises, and dissolves. The last chapter explains the use of Kodacolor, animation,
close-ups, and various other applications of motion pictures. Finally, a few
pages are devoted to the purposes and aims of the Amateur Cinema League.
S. HARRIS
267
SOCIETY OF MOTION PICTURE
ENGINEERS
OFFICERS
1933
President
A. N. GOLDSMITH, 570 Lexington Ave., New York, N. Y.
Past-President
J. I. CRABTREE, Eastman Kodak Company, Rochester. N. Y.
Vice-Presidents
E. I. SPONABLE, Fox Film Corp., New York. N. Y.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
Secretary
J. H. KURLANDER, Westhighouse Lamp Co., Bloomfield, N. J.
Treasurer
H. T. COWLING, Rochester, N. Y.
Board of Governors
H. T. COWLING, 311 Alexander St., Rochester, N. Y.
J. I. CRABTREE, Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
P. H. EVANS, Warner Bros. Pictures, Inc., 1277 E. 14th St., Brooklyn, N. Y.
R. E. FARNHAM, General Electric Co., Nela Park, Cleveland, Ohio.
O. M. GLUNT, Bell Telephone Laboratories, Inc., New York, N. Y.
A. N. GOLDSMITH, 570 Lexington Ave., New York, N. Y.
H. GRIFFIN, International Projector Corp., 98 Gold St., New York, N. Y.
W. C. HUBBARD, General Electric Vapor Lamp Co., Hoboken, N. J.
R. F. MITCHELL, Bell & Howell Co., 1801 Larchmont Ave., Chicago, 111.
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
E. HUSE, Eastman Kodak Co., 6706 Santa Monica Ave., Hollywood, Calif.
E. I. SPONABLE, Fox Film Corp., 850 Tenth Ave., New York. N. Y.
268
OFFICERS
269
E. I. SPONABLE
Vice-President
W. C. KUNZMANN
Vice-President
A. N. GOLDSMITH
President
J. H. KURLANDER
Secretary
J. I. CRABTREE
Past-President
H. T. COWLING
Treasurer
270
OFFICERS
[j. s. M. p. E.
O. M. GLUNT
Governor
H. GRIFFIN
Governor
W. C. HUBBARD
Governor
R. E. FARNHAM
Governor
I i
E. HUSE
Chairman
Pacific Coast Section
P. H. EVANS
Chairman
New York Section
R. F. MITCHELL
Chairman
Chicago Section
Mar., 1933]
COMMITTEES
271
W. T. CRESPINEL
W. V. D. KELLEY
W. C. HUBBARD
J. CRABTREE
J. I. CRABTREE
A. S. DICKINSON
G. EDWARDS
R. M. EVANS
T. FAULKNER
W. CLARK
O. B. DEPUE
D. M. BALTIMORE
B. W. DEPUE
C. D. ELMS
R. EVANS
E. R. GEIB
G. A. CHAMBERS
B. W. DEPUE
O. B. DEPUE
C. L. GREGORY
COMMITTEES
1933
Color
P. D. BREWSTER, Chairman
R. M. EVANS, Vice-Chairman
J. F. KlENNINGER
N. M. LA PORTE
Convention
W. C. KUNZMANN, Chairman
J. H. KURLANDER
Development and Care of Film
R. F. NICHOLSON, Chairman
A. HIATT
D. E. HYNDMAN
E. D. LEISHMAN
C. L. LOOTENS
K. MAC!LVAIN
D. MACKENZIE
Historical
C. L. GREGORY, Chairman
E. THEISEN, Vice- Chairman
N. D. GOLDEN
C. F. JENKINS
G. E. MATTHEWS
Membership and Subscription
H. T. COWLING, Chairman
W. H. CARSON, Vice-Chairman
J. G. T. GlLMOUR
W. W. HENNESSY
J. KLENKE
W. C. KUNZMANN
E. E. LAMB
J. E. MCAULEY
Museum
E. THEISEN, Chairman
C. F. JENKINS
W. V. D. KELLEY
G. E. MATTHEWS
G. E. MATTHEWS
H. B. TUTTLE
M. W. PALMER
J. S. MACLEOD
R. F. MITCHELL
H. RUBIN
W. SCHMIDT
V. B. SEASE
J. H. SPRAY
O. NELSON
T. RAMSAYE
M. L. MISTRY
T. NAGASE
J. A. NORLING
N. F. OAKLEY
E. C. SCHMITZ
T. RAMSAYE
A. REEVES
F. H. RICHARDSON
A. F. VICTOR
272
COMMITTEES
[J. S. M. P. E.
A. A. COOK
W. B. COOK
H. A. DEVRY
E. GALE
Non-Theatrical Equipment
R. E. FARNHAM, Chairman
E. R. GEIB
N. B. GREEN
H. GRIFFIN
L. A. JONES
J. H. KURLANDER
R. P. MAY
R. F. MITCHELL
A. SHAPIRO
C. DREHER
P. H. EVANS
A. C. HARDY
E. HUSE
Papers
O. M. GLUNT, Chairman
G. A. CHAMBERS, Vice-Chairman
G. E. MATTHEWS
P. A. McGuiRE
D. McNicoL
W. C. MILLER
K. F. MORGAN
C. N. REIFSTECK
T. E. SHEA
H. T. COWLING
J. I. CRABTREE
Preservation of Film
W. H. CARSON, Chairman
A. S. DICKINSON
R. EVANS
C. L. GREGORY
T. RAMSAYE
V. B. SEASE
M. ABRIBAT
W. P. BIELICKE
L. BUSCH
F. CAHILL
A. A. COOK
G. A. CHAMBERS
Progress
J. G. FRAYNE, Chairman
C. DREHER
J. A. DUBRAY
R. E. FARNHAM
H. B. FRANKLIN
F. S. IRBY
E. E. LAMB
G. E. MATTHEWS
M. W. PALMER
G. F. RACKETT
P» SCHROTT
H. M. STOLLER
S. S. A. WATKINS
J. O. BAKER
T. BARROWS
G. C. EDWARDS
J. J. FINN
S. GLAUBER
Projection Practice
H. RUBIN, Chairman
J. H. GOLDBERG
C. GREENE
H. GRIFFIN
J. HOPKINS
W. C. KUNZMANN
R. H. McCULLOUGH
P. A. McGuiRE
R. MlEHLING
F. H. RICHARDSON
L. M. TOWNSEND
V. A. WELMAN
E. R. GEIB
H. GRIFFIN
J. H. KURLANDER
Projection Screens
S. K. WOLF, Chairman
W. F. LITTLE
A. L. RAVEN
R. T. RASMUSSEN
H. RUBIN
C. TUTTLE
Mar., 1933]
COMMITTEES
273
R. E. FARNHAM
H. P. GAGE
Projection Theory
A. C. HARDY, Chairman
W. F. LITTLE
W. B. RAYTON
C. TUTTLE
F. C. BADGLEY
B. W. DEPUE
Publicity
W. WHITMORE, Chairman
D. E. HYNDMAN
F. S. IRBY
W. C. KUNZMANN
G. E. MATTHEWS
D. McNicoL
M. C. BATSEL
P. H. EVANS
N. M. LA PORTE
Sound
H. B. SANTEE, Chairman
E. W. KELLOGG
C. L. LOOTENS
W. A. MACNAIR
W. C. MILLER
H. C. SILENT
S. K. WOLF
W. H. CARSON
L. E. CLARK
L. DE FOREST
J. A. DUBRAY
P. H. EVANS
R. M. EVANS
R. E. FARNHAM
C. L. FARRAND
Standards and Nomenclature
M. C. BATSEL, Chairman
H. GRIFFIN
A. C. HARDY
R. C. HUBBARD
L. A. JONES
N. M. LA PORTE
D. MACKENZIE
G. F. RACKETT
W. B. RAYTON
C. N. REIFSTECK
H. RUBIN
H. B. SANTEE
V. B. SEASE
T. E. SHEA
J. L. SPENCE
E. I. SPONABLE
S. K. WOLF
L. J. BUTTOLPH
R. E. FARNHAM
Studio Lighting
P. MOLE, Chairman
C. W. HANDLEY
J. H. KURLANDER
W. J. QUINLAN
Chicago Section
R. F. MITCHELL, Chairman O. B. DEPUE, Manager
B. W. DEPUE, Sec.-Treas. J. E. JENKINS, Manager
New York Section
P. H. EVANS, Chairman M. C. BATSEL, Manager
D. E. HYNDMAN, Sec.-Treas. J. L. SPENCE, Manager
Pacific Coast Section
EMERY HUSE, Chairman C. DREHER, Manager
G. F. RACKETT, Sec.-Treas. J. A. DUBRAY, Manager
SOCIETY ANNOUNCEMENTS
SPRING, 1933, CONVENTION
HOTEL PENNSYLVANIA, NEW YORK, N. Y.
APRIL 24 TO 28, INCLUSIVE
Arrangements for the approaching Spring, 1933, Convention, to be held at New
York, April 24 to 28, with headquarters at the Hotel Pennsylvania, are rapidly
proceeding, the plans including a number of outstanding presentations that will
make it worth every one's while to be present at the meeting. Standardization
is to play an important part in the proceedings. The economy trends in sound
picture production and exhibition that the industry is now showing will be
discussed.
The semi-annual banquet of the Society is to be held on April 26, at the Hotel
Pennsylvania. An evening of pleasure and interest is promised, and all are urged
to make every effort to attend.
Mr. W. C. Kunzmann, chairman of the Convention Committee, is being ably
assisted in his efforts to make the Convention an outstanding success by the
Local Arrangements Committee consisting of:
H. GRIFFIN, Chairman
A. S. DICKINSON S. HARRIS
P. H. EVANS W. C. HUBBARD
J. FRANK, JR. J. H. KURLANDER
O. M. GLUNT H. RUBIN
M. W. PALMER
All technical sessions will be held in the Salle Moderne, on the roof of the Hotel
Pennsylvania. Registration will be opened at 9 A.M., Monday, April 24. The
registration fee will be $3, and the banquet charge $4.50.
Plans are being made to assist out-of-town visitors to the Convention to pass
an interesting time while in New York, and special film programs and trips of
interest will be arranged. Full details of the program, including hotel rates
and other pertinent information, will be mailed to the members of the Society at a
later date. Members and friends of the Society are urged to make every effort to
attend the Convention.
EXHIBIT OF NEW MOTION PICTURE APPARATUS
SPRING, 1933, CONVENTION
Arrangements are being made to hold an exhibit of newly developed motion
picture apparatus, in order to acquaint the members of the Society with the newly
devised tools of the industry. This exhibit will not be of the same nature as the
usual trade exhibit. There will be no booths, although each exhibit will be
allotted definite space, and all exhibits will be arranged in one large room. The
following regulations will apply:
274
SOCIETY ANNOUNCEMENTS 275
1. The apparatus to be exhibited should be new or have been developed or
improved within the past 12 months.
2. Each exhibitor will be permitted to display a card giving the name of the
manufacturing concern, and each piece of equipment shall be labeled with a
plain label free from the name of the manufacturer.
3. A technical expert capable of explaining the features of the apparatus ex-
hibited must be present during the period of the exhibition.
4. A charge for the exhibit will be made in accordance with the space occupied,
as follows: up to 20 sq. ft., $10.00; 20 to 30 sq. ft., $15.00; 30 to 40 sq. ft.,
$20.00; 40 to 50 sq. ft., $25.00.
Please direct requests for space to the General Office of the Society, 33 West
42nd St., New York, N. Y., stating the number and nature of the items to be
exhibited.
PAPERS COMMITTEE
At a meeting held on January 27, at New York, plans were laid for the papers
program of the approaching Convention, announced above. When the arrange-
ments shall have been completed, copies of the final program will be mailed,
together with other information concerning the convention, to all the members
of the Society. The plans include symposiums on the economic trends in the
production and exhibition of motion pictures and a number of demonstrations
of remarkable interest. Among the later will be the presentation to the Society,
by the Projection Practice Committee, of the test film described in Society
Announcements in the February issue of the JOURNAL.
Mr. O. M. Glunt, chairman of the Papers Committee, also indicates that an
interesting session will be devoted to the subject of producing special types of
motion pictures, such as educational, industrial, animated cartoons, and the like.
Considerable attention is being paid also to subjects of direct interest to exhibi-
tors, and it is expected that papers dealing with these subjects will be presented
by a group of men prominent in the field of exhibition.
LAWRENCE C. PORTER
It was with the greatest reluctance that the Board of Governors, meeting on
January 20, 1932, at the Hotel Sagamore, Rochester, N. Y., resolved to accept the
resignation of Mr. Lawrence C. Porter, which had been tendered as a result of
his entering fields of activity remote from the motion picture industry.
Mr. Porter was one of the charter members of the Society and served uninter-
ruptedly in an official capacity from 1921 to date, alternating from Governor in
1921, President, 1922-23, Past President, 1924-25, Governor, 1926, Secretary,
1927-28, President, 1929, Past President, 1930-31, Governor, 1932 to date.
Resolved: That the Board of Governors record its deep appreciation of the many
years of faithful and unselfish service to the Society rendered by Mr. Porter. Per-
haps no other member has contributed so much as has Mr. Porter to the upbuilding
of the Society, his efforts being a natural result of his unbounding energy, industry,
276 SOCIETY ANNOUNCEMENTS [J. S. M. P. E.
integrity, sound judgment, and charming personality. The loss of his services is
deeply regretted by every member of the Board ; it is a great loss to the Society.
STANDARDS COMMITTEE
At a meeting held at New York, N. Y., on February 3, the subject of standard-
izing on a single \ype of film perforation was discussed, in view of difficulties that
seem to exist owing to the use of different perforations for positive and negative
film. The Committee is proceeding to investigate the elements of the problem,
and will report on them at the forthcoming convention, to whatever extent the
intervening time permits.
Other matters include the compiling of a glossary of terms used in color cine-
matography, work on which is now proceeding under the efforts of the Color
Committee, and the desirability of arriving at some form of standardization in
the field of sensitometry were discussed.
A revision of the present booklet of standards is under way, which, when com-
pleted, will form a considerable part of the Committee's report. Other subjects
on which the Committee is working concern the standardization of sprocket di-
mensions, variations in the width of reel hubs, and the possibility of standardizing
the sizes of projection screens.
SOTTND COMMITTEE
On January 9, a meeting of this Committee, held at New York, was called for
the purpose of organizing the work and outlining the plans for the report to be
rendered at the Spring Convention.
Another meeting was held on January 31, at which time the subjects previously
outlined were discussed in greater detail and the framework of the report con-
structed. Among the problems facing the Committee, at the present time are
those concerned with the introduction and use of the wider range of frequency
and volume in recording and reproducing sound. Other subjects deal with the
problems of film development and auditorium acoustics.
MUSEUM COMMITTEE
The Museum Committee, under the chairmanship of Mr. E. Theisen, has
been fortunate in having the active assistance of the personnel of the Los Angeles
Museum during the past few months in improving and extending the S. M. P. E.
exhibit at that museum. New accessions to the exhibit include memoirs of
Vitagraph by J. Stuart Blackton, and an additional presentation by Mary Pick-
ford and Douglas Fairbanks. The R. K. O. Studios have made for the exhibit
a series of devices illustrating the methods of creating artificial rain, wind, rail-
road, and other noises to be synchronized with photographed pictures. There
were obtained also a series of miniatures made by Willis O'Brien, who made The
Lost World, and a collection of manuscripts written by Griffith, Sennett, Florence
Lawrence, King Baggott, and about fifty others, dating from about 1902 to the
present time. Some of these are only six scenes long, and bear itemized expense
accounts of less than a hundred dollars recorded in pencil. Many small accessions
have been received, too numerous to mention, and a considerable amount of ma-
terial has been promised.
Mar., 1933] SOCIETY ANNOUNCEMENTS 277
The chairman of the Committee is making available for the students of the
University of Southern California such facilities as the exhibit may command
in the way of furnishing information for theses and other research for their studies
of motion picture appreciation. (This University is the first to raise the study of
motion picture dramaturgy and technic to the academic rating, offering college
credits for the courses.)
PROJECTION SCREENS COMMITTEE
At a meeting held at New York, N. Y., on February 17, consideration was given
to the desirability, and possibility, of standardizing the sizes of projection screens.
Such standardization, the Committee felt, would eliminate a great deal of waste,
both of time and material, for which the patron of the theater must eventually
pay; would avoid errors in ordering screens; would expedite the shipment of
screens when so ordered, and lead to lower costs.
It was the general opinion of the Committee that the sizes of screen should be
specified in terms of the size of the picture, the specification referring only to the
width of the picture because of the invariable relation (0.600 X 0.825) between
the width and height; thus, a No. 20 screen would refer to a picture area 20 feet
wide and 14.5 feet high.
The Committee also considered the relation between the width of the screen
and the distance of the front row of seats from the screen, as well as the maximum
angle at which the screen should be viewed in order to avoid excessive fore-
shortening of the picture. In addition, plans were discussed for supplying, as
part of the Committee's report, samples of paper chosen according to their
reflectivities, which, when viewed against the screens by the exhibitor, would
furnish an approximation to the reflectivity of his screen on choosing the paper
sample that most nearly matched the screen in respect to brightness.
These subjects will be discussed in detail in the report of the Committee, to be
presented at the Spring Meeting at New York, April 24 to 28.
COMMITTEE ON SCREEN BRIGHTNESS
This Committee consists of representatives of the several projection committees,
who have been meeting recently for the purpose of looking more carefully, and
from all points of view, into the problem of determining what screen characteristics
are found in the field, and what recommendations to the field might be advisable,
both in respect to the screen brightness itself and to methods of measuring it.
The Committee consists of Mr. S. K. Wolf, chairman of the Projection Screens
Committee; Prof. A. C. Hardy, chairman of the Projection Theory Committee;
Mr. H. Rubin, chairman of the Projection Practice Committee; and Mr. W. F.
Little; who have been assisted at their meetings by«Mr. McCandless, of the
Illuminating Engineering Society.
SUB-COMMITTEE ON EXCHANGE PRACTICE
At a meeting held on February 15 at the General Office of the Society, the final
form of the report of the sub-committee, published in this issue of the JOURNAL,
was determined. In addition, plans were laid for the more detailed examination
278 SOCIETY ANNOUNCEMENTS
of some of the subjects mentioned in the report, with the view of arriving at
definite recommendations for the conduct of exchange work that might form the
basis of subsequent reports. The present agenda call for a study of film season-
ing, the character of damage done to film outside the exchanges, splicing of film,
and dimensions of reels.
NEW YORK SECTION
Instead of holding the usual form of meeting this month, the members of the
New York Section were given the opportunity of inspecting the new installations
at the Radio City Music Hall on the morning of February 12. The tour through
the building was led by Mr. R. Cox, of the sound department of RKO Theaters,
who briefly described the equipment of the projection rooms and the general stage
and theater equipment, including the lifts, the lighting, etc. The tour covered
the entire theater, the lounges, lobbies, cafeteria, etc. Thanks are due the RKO
management for the privilege accorded the members of the Section.
SUSTAINING MEMBERS
Bausch & Lomb Optical Co.
Bell Telephone Laboratories
Burnett-Timken Laboratories
Eastman Kodak Co.
Electrical Research Products, Inc.
National Carbon Co.
RCA Victor Co., Inc.
HONOR ROLL
OF THE
SOCIETY OF MOTION PICTURE ENGINEERS
By action of the Board of Governors, October 4, 1931, this Honor Roll was estab-
lished for the purpose of perpetuating the names of distinguished pioneers who are
now deceased:
LOUIS AlME AUGUSTIN L/E PRINCE
WILLIAM FRIESE-GREENE
• THOMAS ALVA EDISON
GEORGE EASTMAN
JEAN ACME LE ROY
PAMPHLETS, BOOKLETS, AND CATALOGUES RECEIVED
Copies of the publications listed here may be obtained free of charge by addressing
a request to the manufacturer named. Manufacturers are requested to send new
publications to the General Office of the Society immediately upon issue.
Bell & Howell Co.: Bulletin describing a new Character Title Writer, to be
used with Filmo Cameras; the unit can be used for making movable-letter ani-
mated titles, the Title Writer being used vertically so that it is not necessary to
fasten the letters to the card. For ordinary titles showing the hand as it writes,
the unit is set up horizontally or at an angle to the table- top. Two 100- watt,
11 5- volt lamps are used, the lamps being silvered on one side so as to avoid the
need of reflectors. They are mounted on joint and swivel supports so as to permit
their proper adjustment for avoiding reflection into the camera from glossy
subjects and to permit shadow effects to be obtained. Address: 1801 Larch-
mont Ave., Chicago, 111.
Du Pont Film Mfg. Corp.* Bulletin NF-2, describing du Pont dupac negative.
This is a bi-pack combination of two special negatives to be used in standard
cameras, for making two-color separation negatives. Only a moderate initial
outlay is necessary for making the necessary camera changes and special maga-
zine equipment. It is stated that the means employed in the front negative for
filtering the light make it possible to retain the full working speed and contrast
of the front film emulsion, and at the same time to filter accurately and uni-
formly the light passing through to the rear negative. It is also said to be possible
to hypersensitize the negative and to process it without contaminating the solu-
tions with dyes. Address: Parlin, N. J.
The Educational Screen, Inc.: A booklet entitled 1000 and One, The Blue
Book of Non-Theatrical Films. A classified list of the films obtainable in a great
many subjects. Full information is given concerning the title, number of reels,
nature of the subject, and distributor, for 16-mm. silent, 16-mm. sound-on-disk,
35-mm. silent, and 35-mm. sound-on-film or disk. The subjects embrace most
phases of science, sociology, government, health and hygiene, industry and
engineering, literature and drama, psychology, war — naval and military. Re-
ligion, comedy, and travel subjects are included. Address: 64 E. Lake St.,
Chicago, 111.
General Radio Co.: Catalogue G, lists and describes the construction and uses
of electrical measuring apparatus and accessories such as resistance devices,
condensers, inductors, frequency and time measuring devices, oscillators and
amplifiers, bridges, generators, instruments for measuring modulation and dis-
tortion, oscillographs, etc. Address: Cambridge A, Mass.
General Radio Co.: The General Radio Experimenter, Vol. vii, No. 7, de-
scribes the principles and applications of the stroboscope in studying the motions
of objects; the elementary mathematical theory of the stroboscope is also pre-
sented briefly. The Edgerton Stroboscope (type 548- A) employs a high-intensity
279
280 PAMPHLETS, BOOKLETS, CATALOGUES
mercury arc, the flash of which has a duration of only five microseconds, during
which interval an object moving at the rate of a mile a minute traverses a dis-
tance of only five-thousandths of an inch. Fundamental synchronism can be
achieved at rotational speeds up to 10,000 r.p.m. Address: Cambridge A,
Mass.
Globe Automatic Sprinkler Co.: Bulletins describing the model C Dry Pipe
valve and the Saveall Airomatic Sprinkler System. Details are given of the con-
struction and design features of the equipment, and the manner of making the
installations. The Saveall Sprinkler System is designed particularly for installa-
tions where the supply of water is limited and where the Standard Automatic
sprinkler systems may not be used economically. Address: 2035 Washington
Ave., Philadelphia, Pa.
Jenkins & Adair, Inc. : Circular describing the Phonopticon and Contr otophone.
These are sound-on-disk reproducing devices, for which special disks are prepared
having recorded on them sub-audible (50 cycle) notes, lasting but a brief interval
and recorded at selected points in the sequence or scenario. The 50-cycle note,
upon actuating the pick-up, is diverted from the reproducing amplifier by means
of a selective filter, and is made to operate a relay. In the Phonopticon the relay
is made to open and close the circuits of a motor driven mechanism for changing
lantern slides at the instants when the 50-cycle notes occur on the disk. The
Controlophone is a special adaptation of such a system for sales promotional and
educational purposes. Both types of instruments are mounted in suitable cabi-
nets, and may be used for presenting lectures, travelogues, sales talks, etc. Ad-
dress: 3333 Belmont Ave., Chicago, 111.
RCA Victor Co.: A booklet describing the new RCA Victor sound recording
system having the features of increased dynamic range, increased frequency range,
and decreased ground noise. The applications of the system to the needs of
motion picture theaters are described, and a general description of the principles
of the system is presented. The various design and construction features of the
component parts of the equipment are described in detail.
Victor Animatograph Corp.: This circular announces a new 500- watt Mazda
lamp, produced by the General Electric National Lamp Works, which is suitable
for use in the Victor Model 10FH Premier Hi-Power 16-mm. projector. Al-
though this projector, having a built-in lamp resistor in the base, is ordinarily
supplied with the 400- watt lamp, it will accommodate the new lamp without altera-
tions of any kind. The 500-watt lamp is supplied only when so specified. It
operates at 100 volts, and should not be confused with the older T12 500-watt,
110-120- volt lamp. The new lamp employs an 8-coil biplanar filament, and
provides greater illumination. Address: Davenport, Iowa.
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
Volume XX APRIL, 1933 Number 4
CONTENTS
Page
Composite Photographic Processes H. D. HINELINE 283
The Optical-Photographic Principles of the Agfacolor Process.
F. WEIL 301
The Production of Animated Cartoons W. GARITY 309
A Method of Measuring Axial Chromatic Aberration in an
Objective Lens W. HERRIOTT 323
A New Way of Splitting Seconds C. H. FETTER 332
A Method for the Calculation of the Correct and Most Eco-
nomical Concentrations of Elon and Hydroquinone in a
Borax Developer for Motion Picture Film
A. M. GUNDELFINGER 343
Officers 355
Society Announcements 356
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
SYLVAN HARRIS, EDITOR
Board of Editors
J. I. CRABTREE, Chairman
L. DE FOREST A. C. HARDY E. LEHMANN
O. M. GLUNT F. F. RENWICK
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.
Publication Office, 20th & Northampton Sts., Easton, Pa.
General and Editorial Office, 33 West 42nd St., New York, N. Y.
Copyrighted, 1933, by the Society of Motion Picture Engineers, Inc.
Subscription to non-members, $12.00 per annum; to members, $9.00 per annum,
included in their annual membership dues; single copies, $1.50. A discount
on subscriptions or single copies of 15 per cent is allowed to accredited agencies.
Order from the Society of Motion Picture Engineers, Inc., 20th and Northampton
Sts., Easton, Pa., or 33 W. 42nd St., New York, N. Y.
Papers appearing in this Journal may be reprinted, abstracted, or abridged
provided credit is given to the Journal of the Society of Motion Picture Engineers
and to the author, or authors, of the papers in question. The Society is not re-
sponsible for statements made by authors .
Entered as second class matter January 15, 1930, at the Post Office at Easton,
Pa., under the Act of March 3, 1879.
COMPOSITE PHOTOGRAPHIC PROCESSES*
H. D. HINELINE**
Summary. — The author traces in this paper the development of composite photo-
graphic processes, in terms of the patent history of the art, from its beginning to April
1, 1932. For convenience, the art is divided into three phases, namely: the mask
process, the projection process, and the color-separation process. Each of these lines
has evolved into several variants, the development of which is traced through the patent
literature.
Composite photography may be described as the process of making
pictures in which the background and the foreground are obtained
from separate sources, and combined to produce the completed
picture. To obtain a satisfactory combination, some means must
obviously be provided to prevent overlapping of the respective
picture-element images. Various means have been proposed and
described chronologically in various United States patents, which
form the original sources of material for the following descrip-
tion of the suggested processes.
The patent literature describes three kinds of processes, which
differ broadly in their various details. The earliest process in point
of time may be called the mask process; the next may be called the
projection process; and the third may be called the color-separation
process. The mask process has developed along several lines,
yielding a number of variants that differ considerably among them-
selves, although all utilize some kind of opaque mask or shield for
separating the components of the picture and for avoiding such
difficulties as overlapping, "ride," ghosting, and fringing. Also,
certain of the suggested processes utilize elements of all three of the
processes as hereinafter differentiated.
As is usual in commercial photographic work, comparatively little
information has been published, either in the technical or popular
* Received March 7, 1932.
** Patent Solicitor, New York, N. Y.
283
284 H. D. HINELINE [J. S. M. P. E.
journals, bearing on these composite processes, and the most detailed
information seems to be found in the patented art.
MASK PROCESSES
The first patent publication of a composite photographic process
was patent No. 149,724, issued on April 14, 1874, to C. M. Coolidge.
This patent describes, of course, only a still photographic process,
as it was issued long before the days of motion pictures. But the
principle of holding a card, screen, or mask, carrying the desired fore-
ground matter, in front of undesired parts of the subject in order to
achieve a cartoon effect, is the forerunner of many of the later
processes, and carries the germ of the idea from which the later-
developed mask, screen, and cartoon processes grew.
During the twenty years following the issuance of this patent,
the foundation was laid for all the other types of composite processes,
as will later be described; the patents that were published related,
mostly, or at first, to still photography only, later branching out into
the motion picture art soon after the advent of the screen. For some
reason effort seems to have been concentrated for a time on the
processes other than the mask process, with the result that we do
not find another patent for a screen or mask process until October
19, 1915, when patent No. 1,156,896 was issued to J. E. Garrette.
Nevertheless, much more work seems to have been done on the mask
and screen processes than on all the other processes, if one may judge
by the number of patents that were issued.
The Garrette patent describes the use of a combination of colored
lantern-slide and motion picture film for simultaneous projection,
the slide having a portion prepared to be occupied by the small field
of the moving picture. The stationary slide thus becomes, in effect,
a screen or mask cooperating with the motion picture, and is claimed
so to act in the patent, which also contains claims referring to the
projector. The patent has, however, expired.
The first mention of the device that may be called a traveling mask
is found in patent No. 1,226,135, issued on May 15, 1917, to R. V.
Stambaugh. In this patent is disclosed a motion picture negative,
which may be a cartoon if desired, having a clear space in each frame.
This negative, which may be regarded as the traveling mask, is placed
in the camera together with an unexposed film, the camera then
being trained on a card bearing the matter to be added to the first
negative. The light from the white portions of the card prints the
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 285
negative, while the lettering or other matter on the card is photo-
graphed directly on the unexposed film through the clear portion
of the negative. The object of the process is to produce a number of
advertising films, respectively carrying the names of different ad-
vertisers, and different cop/, but using only a single negative of the
action or cartoon. The process is aimed at reducing the cost of
advertising films. It may be of interest to note that while the
patent monopoly has yet to remain in force about two more years,
the claims are very restricted, being limited to the process of com-
bination printing of a negative and photographing of other matter.
As this is the actual invention, the claims are properly limited to
such a scope.
The next patent, chronologically, applies the idea of the Coolidge
patent to the making of animated cartoons. This is patent No.
1,261,648, issued April 2, 1918, to P. H. Terry. It teaches a method
of making animated cartoons by sketching the stationary parts of
the picture upon a card that is blackened where the action or figures
are to be, the figures and action being sketched upon another series
of cards, blackened where the background is to be. Each frame of
the film is then made by a double exposure, using the background
sketch and the action mask for one exposure, and the action
sketch and background mask for the other exposure. The claims
are based on the superposition of successive exposures, and ac-
cordingly are rather limited in scope.
The first mention of a fixed mask used inside the camera is found
in patent No. 1,269,061, issued June 11, 1918, to Norman Dawn.
In the process disclosed photographs are made of the foreground and
action behind a vignette or screen placed inside the camera so as to
leave the top and background portions of each frame unexposed.
The background is then added by photographing a card or drawing
of the desired scene, the foreground of which has been rendered non-
actinic. The claims are few and narrow in scope.
The complete disclosure of the process using a traveling mask as
now known is first found in patent No. 1,273,435, issued July 23,
1918, to F. D. Williams. In this process, the action is photographed
against a black background, yielding a negative that is transparent
except for the action. A print of this negative is then made in such
a way that the area of the action is left transparent, the background
area being made opaque and as dense as possible by intensification.
The print thus produced is the first mask. A print is then made
286 H. D. HlNELINE [J. S. M. P. E.
from this mask, producing the second or reverse mask. The action
negative and the first mask are placed over the raw film and printed;
then the background negative and the second mask are substituted
and the raw film is printed again. The first exposure of the action
is protected by the mask, the area of the background being protected
from fogging by the first mask during the first printing. The dis-
closure suggests also that the first and second printing may be both
of action, as a duplication of a single actor. The claims of the
patent are rather broadly drawn to the double masking features of
the invention.
A very poorly prepared patent, No. 1,279,099, issued September
17, 1918, to C. A. Gilbert, attempts to describe a process of com-
bining with a drawn background a photographed silhouette of the
action, and makes such claims; but the description is more sug-
gestive than detailed, as most of the photographic steps, which seem
to be important, are left to the imagination of the reader.
An interesting, but perhaps somewhat impracticable variant,
which suggests but probably is not quite a traveling mask, is found
in patent No. 1,296,471, issued March 4, 1919, to L. S. Brainerd.
The system disclosed consists of a camera, in front of which is posi-
tioned a guide and a means for producing intermittent motion of a
member carrying a series of sketches forming the successive views of
an animated cartoon. Beyond the strip, in the same field of view,
there is also provided a stage for action by ordinary actors. The
actors on the stage and the cartoon on the strip are then combined
on a single film ; but it does not affirmatively appear that the cartoon
strip is transparent, as would be necessary for a real traveling mask.
The claims are narrowly drawn to the combination of cartoon and
action.
The double mask system of the Williams patent is extended to
animated cartoons, made from life, in patent No. 1,355,648, issued
October 12, 1920, to L. E. Brownley. The complementary masks
are, however, made manually rather than photographically, so as to
permit the desired modification of the outlines of the characters.
The claims are, of course, restricted in scope by the previous
appearance of the Williams patent.
A better disclosure of a process for making cartoons by using a
double set of traveling masks is found in patent No. 1,375,918, issued
April 26, 1921, to C. F. Lederer. In this patent the process described
requires that silhouettes corresponding to the outlines of the action
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 287
or foreground matter, as well as drawings of the action, be made
manually. A single drawing of the background is then photographed
through the appropriate mask, and the successive drawings of the
action are photographed on the same film and frame through the
other mask. The patent contains a considerable number of claims,
not very broad, but covering the invention well.
Movement of a simple mask crosswise within the camera is dis-
closed in patent No. 1,397,602, issued to W. O. Owen, on November
22, 1921. This seems to be a minor matter, but the issue of the
patent may be noted.
An interesting variant of the fixed mask idea is seen in patent
No. 1,464,054, issued on August 7, 1923, to F. D. Williams. The
desired negative of the action is printed on the positive stock, in a
camera which is used as a printer and which takes both the negative
and the raw film stock, by light reflected through the camera lens
from a card, the reflective power of which is modified so that light is
reflected only to the parts of the negative film to be printed. Supple-
mentary cards may be used to produce a composite, or double, ex-
posure so as to combine separately photographed foreground and
background.
Another patent, disclosing a process of somewhat doubtful utility
is No. 1,476,885, issued December 11, 1923, to D. W. Griffith, in
which a screen having an opening is used as an intermediate ground,
with the foreground action in front, and the opening closed. After
photographing the action the film is run back in the camera, the
screen opening is cleared, and a sketch behind the opening is illumi-
nated and photographed. The reason for the sequential, rather than
simultaneous, photographing of the two does not appear.
An interesting but somewhat doubtful variation of the traveling
mask method is disclosed in patent No. 1,503,731, issued August 5,
1924, to J. B. Walker. In this system two simultaneous negative
exposures of the foreground and action are made; one of these is
developed and used to make a printing strip for relief type; ink or
dye is applied to the other negative exposure, as yet undeveloped,
to protect the foreground while the background exposure is being
added. Questions may be raised as regards the shrinkage of the film
and the registration.
Patent No. 1,508,509, issued September 16, 1924, to L. F. Douglass,
contains some interesting claims relating to the use of supplementary
masks in the printer for combining foreground and background.
288 H. D. HINELINE [j. S. M. P. E.
A similar structure in the taking camera is shown in patent No.
1,543,065, issued June 23, 1925, also to L. F. Douglass.
A convenient method of making complicated masks to be used in
the camera is shown in patent No. 1,572,315, issued February 9,
1926, to E. Scholl. In this method a metal strip is coated with
emulsion, the desired background scene is photographed on the
strip, the desired solid portions being protected by resist and the etch-
ing being done through the desired openings.
Still another variant of the early Coolidge patent is described in
patent No. 1,574,464, issued February 23, 1926, to J. Bartholowsky,
disclosing a photographic system in which a miniature model of part
of the background is placed near the camera, while other portions
of the desired scene, of full size and visible through openings in the
miniature, are placed farther away. The claims seem to be limited
to the use of a miniature above a reference level.
Stationary supplemental masks placed outside the camera are dis-
closed in patent No. 1,576,854, issued March 16, 1926, to J. F. Seitz.
These masks are used with a rigid frame and track which holds the
camera and mask in fixed alignment. The masks are made by pro-
jecting a photograph from and in the same camera. This patent
has been reissued as No. Re 17,125.
Patent No. 1,589,731, issued June 22, 1926, to F. D. Williams,
makes a somewhat uncertain attempt at disclosing a composite proc-
ess in which the action and lower portion of the background are
photographed, printed, and projected to a screen, a sketch of the
remainder of the background being made on the screen which is then
photographed and combined with the foreground and action in ways
not clearly described. This patent also has been reissued, as No.
Re 17,330.
In using traveling mask processes, the most serious technical prob-
lem is that of registering the mask accurately with the various nega-
tives and the print film, in view of the differences of shrinkage among
the various films. The first disclosure of means designed to avoid
this difficulty appears in patent No. 1,610,410, issued December 14,
1926, to F. F. Baker. Arrangements are made for splitting the light
so as to be able to expose the action negative and the mask film
simultaneously, and suitable means are provided in processing for
equalizing the shrinkage. The mask film is then used in photograph-
ing the background. The developed foreground and background
negatives are then cemented together, and printed in an optical printer.
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 289
Patent No. 1,616,237, issued February 1, 1927, to J. F. Seitz,
is a companion patent to the previously mentioned patent No.
1,576,854. Minor modifications of the system are described, in
which an enlargement is used as a mask, part of the enlargement
being cut away so as to permit the use of ordinary stage and actors
at a greater distance.
An excellent description of the traveling mask process, and its
application to the two-color subtractive process known as "Techni-
color," is given in patent No. 1,641,566, issued September 6, 1927,
to J. A. Ball. The claims are directed toward two-color compositing,
but the description shows the features involved in obtaining register
in the traveling mask process, and also means for obtaining color
balance in the composite film. In the process as described the fore-
ground and background are combined by processing the color-separa-
tion silver print images in combination with the masks, before the
color printing is done, compositing being done separately for each
color.
The extent to which masks may be used outside the camera is
shown in patent No. 1,669,963, issued May 15, 1928, to P. W. Young-
blood. The process requires an enlargement of the desired back-
ground scene, with a part cut out where the action is to occur. The
cut-out opening is then backed by a larger or full-scale enlargement,
at a greater distance from the camera, the actors performing in the
space between the two enlargements. The patent has only a single,
very narrow claim.
An interesting means of obtaining the traveling mask is shown in
patent No. 1,697,315, issued January 1, 1929, to M. Handschiegl.
The foreground exposure is made upon a film that is not color-sensi-
tive, before a non-actinic screen. The film is then developed, rinsed,
and dried without being fixed, and the mask is made on panchromatic
film by exposing it to light to which the first film is not sensitive, such
as red light. The background exposure may then be added to the
first film, using the mask to protect the foreground exposure. The
film is then developed a second time, fixed, etc., yielding the desired
composite negative.
A traveling mask substitute is suggested by N. Osann in patent
No. 1,698,448, issued January 8, 1929. The exposure of the fore-
ground is made against a non-actinic field, and developed. Then,
without fixing it, the developed image is toned, to render it opaque;
and the dried film is reexposed to the desired background ; it is again
290 H. D. HlNELINE [J. S. M. P. E.
developed, fixed, etc., after which it is printed. Although this
process avoids problems of registration, it substitutes those of obtain-
ing tone balance, and introduces chemical and grain difficulties.
An elaborate description of a simple double exposure process is
found in patent No. 1,737,021, issued November 26, 1929, to G. B.
Pollock. A test portion of the 'original partly exposed action film
is used with a chart board to aid in preparing a sketch of the sub-
stitute background. It does not appear that by this process a whole
new background will be supplied, but that only a portion of the back-
ground, separated from the action, will be replaced.
An odd suggestion is made in patent No. 1,771,029, issued July 22,
1930, to J. Burkhardt. Successive frames carry the action and the
background alternately, the background frames having opaque por-
tions corresponding to the action as shown in the adjacent frames.
The adjacent frames are then projected together, for the effect of
relief, seemingly a pseudo -stereoscopic effect. A modification in
which the frames are placed side by side, instead of in sequence, is
shown in patent No. 1,785,336, issued December 16, 1930, and yet
another in patent No. 1,801,656, issued April 21, 1931.
R. J. Pomeroy discloses, in patent No. 1,818,354, issued August
11, 1931, the use of a half -silvered mirror and two cameras, one camera
making the action negative, and the other making the mask, using a
fuller exposure on very coiitrasty working stock. The mask film
is then developed, etc., and used as a protection for the action
exposure on the other film during the exposure of the back-
ground.
A process in which some of the steps of the animated cartoon proc-
esses are used is shown by O. Chouinard, in patent No. 1,827,282,
issued October 13, 1931. In this process two similar negatives are
made simultaneously in separate cameras. One negative is de-
veloped and projected on a screen on which the background is then
drawn, a non-actinic area being left where the foreground appears.
The frames of the other film, exposed to the action, are then re-
exposed one by one to the drawing, so as to add the desired back-
ground, the necessary changes in the non-actinic area of the
drawing being made between frames according to the changes in
position of the action.
What seems to be a worth-while detail in the process of making the
traveling mask is shown in patent No. 1,840,669, issued January 12,
1932, to M. Handschiegl. This patent describes the use of two super-
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 291
posed films in the camera, both films being exposed to the action.
One, preferably the rear one, is developed for contrast, and is then
positioned in front of the other, still undeveloped, so as to protect
the exposure of the action during the exposure of the background.
A companion patent, No. 1,840,670, issued to the same inventor
and on the same date, gives a terse summary of the traveling mask
processes, and seeks to claim a process in which a positive print of the
desired background is used with the mask, necessitating only one
mask. The claims, however, seem narrow, and of doubtful validity.
The mask and screen processes described above are designed with
the idea of photographing the foreground and the background sepa-
rately, and of obscuring complementary areas of the film during one
or both exposures by means of an opaque mask, or shield, this being
the essential element, whereby the composited element is fitted into
the opening of the other exposure made by the shield.
PROJECTION PROCESSES
It has, of course, long been known that stage settings could ad-
vantageously be reproduced from full-size drawings, and it seems to
have been early appreciated that a stage background could be pro-
duced by optically projecting a small transparency, such as a lantern
slide, on a translucent screen serving as a back drop, as is shown in
patent No. 486,606, issued to F. Seymour on November 22, 1892.
This patent shows a stage setting consisting of a translucent screen
upon which the scene is projected by a stereopticon, the actor being
positioned in front of the screen. Photographing of the stage and
action is not, however, suggested in this patent.
The first suggestion of composite photography, for a still picture,
by directly photographing a normal figure or foreground against a
projected background, is found in patent No. 656,769, issued August
28, 1900, to R. M. Hunter. However, this patent involves photo-
graphing separately the foreground or figure, and the background,
probably because of differences in illumination, and the difference in
exposure time for the two. It was, of course, possible to do this in
still photography, where the subject could stand still long enough to
become the necessary silhouette before the projected background.
The process of simultaneously exposing the foreground and the
background by projection, in still photography, is disclosed in patent
No. 1,053,887, issued February 18, 1913, to H. Sontag. This patent
also describes the use of a non-actinic front surface on the translucent
292 H. D. HINELINE [J. S. M. P. E.
screen, for reducing the effect of front light in degrading the contrast
of the projected background.
A variant, in which the projection screen covers part of the subject,
is shown in patent No. 1,133,311, issued March 30, 1915, to W. W.
Newcomb, also for still photography. This patent shows front
projection, and photographic exposure from the front. (The pro-
jected matter is described as pictures of women's clothing. The
subject would stand behind the screen, her head showing above it,
and be photographed to show how she would appear in her new
clothes.)
What may be considered to be an off-shoot from the direct line of
development of projection processes is found in patent No. 1,263,355.
issued April 16, 1918, to P. Artigue. This patent describes a process
for making animated shadowgraphs, in which the background scene
is sketched on a translucent screen illuminated from the rear by a
point source of light, the desired shadows being thrown upon it by
the actors, to be photographed together with the background.
The first suggestion of simultaneous projection and photographing
for motion picture work is found in patent No. 1,270,778, issued
July 2, 1918, to A. D. Brixey. This patent discloses means for add-
ing dialog inscriptions to a motion picture film (before the advent of
sound) by projecting the successive frames upon a translucent screen
before the camera, and holding up to the screen a card inscribed with
appropriate lettering and provided with a "leader" that would follow
the mouth of the character supposed to be speaking. The screen
and card are then photographed to produce the desired film.
Still another off-shoot process is disclosed in patent No. 1,278,117,
issued September 10, 1918, to J. S. Dawley, describing a process in
which the background is inserted into the picture by reflection from
a plate of glass in the line of sight of the lens, the actors being in
the direct line. The way in which ghosting is avoided is not given,
and this lack may be fatal to the process. It is doubtful whether
this should really be considered as a projection process.
Another forward step is shown in patent No. 1,301,538, issued to
L. S. Brainerd, on April 22, 1919. A coupled projector and camera
operate in synchronism. The camera and the projector are placed
side by side before a stage, which has an opaque screen at the rear.
The background is projected upon the screen and actors together,
no provision being made to prevent the projected image from being
superposed on the actors. It may be noted that all the claims in
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 293
this patent are drawn with the phrase "cartoon pictures" for the
projected material.
Attention may well be called again to the first of the Brainerd
patents, No. 1,296,471, previously mentioned, as the claims in it may
well be more pertinent to a projection process than to a mask process.
The third Brainerd patent, No. 1,307,846, issued June 24, 1919,
carries the idea still farther by claiming the process, although the
disclosure is much the same as that of the second Brainerd patent,
No. 1,301,538.
It may be noted that at this stage, work on projection processes
seems to have languished for a considerable time, nearly ten years,
the Brainerd patents having been applied for in 1915, and the next
issued patent appearing in 1925. This patent, No. 1,601,886, was
issued on October 5, 1926, to E. Schufiftan, and discloses a camera,
a partly silvered mirror in front of the camera lens, a screen on which
the background is projected adjacent to one face of the mirror, and
the stage setting and actors before the other side of the mirror, the
two being composited by reflection and direct vision through adja-
cent reflecting and transmitting areas of the mirror. A synchroniz-
ing drive connection between the camera and the projector is well
shown. All the claims seem to be limited by the inclusion of the
partly silvered mirror.
A very nearly similar system is disclosed in another Schufftan
patent, No. 1,690,039, issued October 30, 1928. These patents
must be examined in the original, to see the minutiae of detail, and
the differences in the respective disclosures, and claims.
The projection idea is applied to the manufacture of animated
cartoons in patent No. 1,760,156, issued May 27, 1930, to N. H.
Mann. The principal function of the projection, however, is to
produce photoprints from the motion negative, from which photo-
prints cut-outs are applied to the successive cartoon card sketches.
The last patent to be mentioned in the field of projection composit-
ing is No. 1,827,924, issued October 20, 1931, to F. D. Williams,
showing a number of details of value in projection processes, including
the displacement of the projector sidewise from the normal line of
the screen so as to avoid the "hot spot," the use of two projectors
throwing different picture components upon the screen, the use of
superposed films in the projector, double exposure of the camera film
to successively projected images from the projector, etc.
The projection method of compositing is thus shown to have been
294 H. D. HINELINE [j. S. M. P. E.
brought to a high stage of development, becoming convenient and
flexible in application, and possessing substantially fewer difficulties
than are inherent in the mask processes. The most serious objection
to the process is said to be the loss of detail and definition in the back-
ground copied from the screen.
COMPOSITING BY COLOR-SEPARATION METHODS
Another interesting process involves the differentiation between
the foreground and the background by means of color combinations,
the process, broadly stated, being that of using a positive trans-
parency of one picture component, which is transparent to the fore-
ground image but is printed on the film for the background image.
This process has been largely developed by Dunning and Portiere)',
but a small amount of prior art is worth noticing.
The first item of this prior art is patent No. 858,162, issued June
25, 1907, to F. J. Dischner, which discloses a process in which a
positive of the desired background is positioned in front of the nega-
tive material in the camera, and an illuminated back-screen used
behind the subject. The light from the back-screen prints the back-
ground positive on the negative material, as a negative; while the
foreground subject makes a silhouette against the back-screen, and
prevents exposure over the foreground area. The positive and the
lighted screen are then removed, and the foreground subject is lighted
and photographed without change of position. Another patent,
No. 967,025, issued August 9, 1910, to Leonard and Oldaker, shows a
camera structure adapted to this process. Both are for still rather
than motion picture photography.
The first appearance of the idea of employing color for the separa-
tion occurs in patent No. 1,613,163, issued January 4, 1927, to C. D.
Dunning. This patent suggests that the original negative of the
background be printed to a positive, which is then color toned and
tinted, placed into the camera with panchromatic film stock, and the
foreground subject photographed through it against a colored back-
ground. As far as can be judged, the idea is to make the positive
uniformly transmissive to white light, but non-uniformly trans-
missive to colored light, thereby making possible the exposure by
white light passing through it from the foreground subject, and the
printing of the positive simultaneously by colored light en silhouette
around it.
A much clearer disclosure is found in patent No. 1,673,019, issued
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 295
June 12, 1928, to R. J. Pomeroy. This patent describes the use in
the camera structure of a dye positive of the desired background,
with panchromatic negative stock; and a back curtain, placed
before the camera and behind the action, of a color contrasting with
the dye positive, the action being illuminated with light of the same
color as the dye positive. The foreground light then passes through
the positive unhindered, making the exposure ; while the background
light, en silhouette, prints the positive, making the background ex-
posure. This patent appears to contain the broadest claims to the
process.
The next patent in order is No. 1,686,987, issued October 9, 1928,
also to R. J. Pomeroy, which shows a process for combining separately
photographed action and background in a printer by the aid of colored
lights. The action is photographed before a white screen, so as. to be
surrounded by an opaque mat. From this negative is made a dye
positive, in which the action printed in, say, blue, is surrounded by a
red field. This is combined with a light print of the background also
dyed blue. The two are superposed on panchromatic stock in the
printer, and printed by mixed red and blue light, thus producing the
desired composite negative. The light blue background print has a
negligible effect under the heavy blue foreground action, which is
printed by the blue light, but the light blue print strongly contrasts
with the red light through the silhouette around the action. This
is as ingenious and interesting a process as is found in the art, because
of the nice balance of elements; although it is far from the simplest
to work, nor does it promise better results than other processes.
Still another variant is shown in patent No. 1,715,510, also issued
to R. J. Pomeroy, on June 4, 1929. In this form, the action is photo-
graphed before a non-actinic background, the negative being toned
blue, on a. clear field. A blue-dye background-negative-transparency
is positioned in the camera in front of a panchromatic film, the camera
being trained on the action negative, which is illuminated with red
light. The negative is front-lighted in blue, and the respective
lights print the two negatives on the panchromatic film in the
camera.
A nice outline of the color differentiation compositing process
with improvements is found in patent No. 1,776,269, issued Septem-
ber 23, 1930, to R. J. Pomeroy, the improvement specifically disclosed
being that of using a negative film of the background positive print,
dyed in a color such as yellow, with the blue background positive
296 H. D. HINELINE [j. S. M. P. E.
print, so as to counterbalance absorption, by the print, of light of
the same color as the print.
The latest of the patents dealing with this process is No. 1,788,740,
issued January 13, 1931, also to R. J. Pomeroy, disclosing an interest-
ing procedure of using the color-separation method with a silver
print for the background scene. The process employs a split light
beam with color filters, complementary lights on action and back
screen, and panchromatic film, the foreground and background ex-
posures being made on opposite sides of the film. One light beam
emanates from the action; the other is en silhouette around the
action, and prints the silver positive on the reverse side of the film.
This, of course, involves the problem of registration of the two beams
on the opposite sides of the negative film.
GLASS SHOTS
Another procedure, which has attained to a separate status in the
field, is identified by the phrase "glass shot." In this process, in
its customary form, the desired background is painted, in miniature,
on a plate of glass which is placed near, and in front of, the camera.
Part of the glass is left clear so that the action may be photographed
through it. This process is strictly a variant of the stationary mask
process, but having attained to a separate field, may be separately
treated.
The first mention of a process suggesting this method occurs in
patent No. 45,449, issued December 13, 1864, to Wm. Callcott.
This patent discloses simply a stage illusion, in which successive glass
plates, on which the desired scenery is painted with light-translucent
paint, are successively illuminated, the rear ones being visible through
the front ones. No photography seems to have been involved in
the process. »
The next suggestion of interest is found in patent No. 1,019,141,
issued March 5, 1912, to A. Engelsmann. A glass plate serves to
reflect light from depressed screens carrying moving pictures of the
actors only, without the background. The glass is placed in front
of a painted drop; a pseudo-stereoscopic appearance is effected,
the motion picture actors being expected to give the impression of
being in front of the drop.
An interesting use of a glass plate — not quite a "glass shot" as
now understood — is shown in patent No. 1,235,871, issued August 7,
1917, to C. M. Aument. This patent discloses a cartoon process,
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 297
in which the permanent background is drawn on the glass, the mov-
ing figures being sketched on it in successive positions and guide
sketches being used on the back of the glass to aid in making the main
sketches, which are then photographed. Still another cartoon process
employing a glass plate is disclosed in patent No. 1,263,355, issued
April 16, 1918, to P. Artigue, previously mentioned. The desired
background is sketched on a translucent screen, and the actors are
silhouetted on the screen by a single rear light. This is not quite a
"glass shot," although it has most of the elements of a glass shot.
Still another approach to the glass shot idea is found in patent No.
1,278,117, issued September 10, 1918, to J. S. Dawley. In this
process, a glass screen in front of and near the camera has projected
upon it the desired background scene, while the actors are on a screen
stage of normal size, beyond the glass.
Another interesting suggestion is found in patent No. 1,296,471,
issued March 4, 1919, to L. S. Brainerd, and previously mentioned.
It is of interest in that it shows means for photographing both the
actors and a miniature sketch with the same camera, on the same
film.
The next pertinent patent to be issued was No. 1,372,811, to W. L.
Hall, on March 29, 1921. This patent shows in elaborate detail the
steps to be taken in matching the miniature on the glass, in tone and
perspective, to the desired foreground by means of targets, charts,
and tone scales, and gives a good outline of the whole procedure.
The claims refer to the broad process, and to the details.
It may be noted that glass shots are made with the miniature of
the background on a glass plate as a matter of convenience; however,
it does not appear that this is the only possible way, since similar
results may be attained with the miniature on an opaque sheet in
which openings are cut for the line of sight to the action in full scale,
or in the solid, with similar openings.
This method of working is disclosed in patent No. 1,476,885,
issued December 11, 1923, to D. W. Griffith. Here is used a screen
having a hole cut in it. The screen is appropriately painted, and an
actor may work in front of it, while another screen and actors may be
visible through the opening.
The "glass shot" idea is carried still farther in patent No. 1,540,213,
issued June 2, 1925, to O. R. Hammeras. The system disclosed is
stated to be an improvement over the Hall patent No. 1,372,811,
which improvement seems to lie in the idea of building sets to a point
298 H. D. HlNELINE [J. S. M. P. E.
just above the heads of the actors, and completing the top of the set
by a painted miniature on a glass plate. The claims seem to be drawn
to the idea of marking the outlines of the fixed scenery on the glass
plate and completing the miniature from such guide lines, thereafter
photographing from and through the glass.
The equivalent of a glass shot, that is, a miniature drawn or con-
structed of opaque material, without the glass, is described in patent
No. 1,574,464, issued February 23, 1926, to J. Bartholowsky. This
patent shows a bottom portion of a set constructed full-scale for the
actors; and a top portion, in miniature and much nearer the camera,
with the joining margins aligned before the camera, the perspective
of the miniature part of the set being adapted to its distance from the
camera.
The details of "glass shots" are still further developed in patent
No. 1,742,680, issued January 7, 1930, to P. Artigue. The main
feature of the disclosure is the use of filter colors, or dyes, on the glass
to modify the appearance of the scene behind the glass.
The last patent to be noticed on the subject of glass shots is No.
1,764,490, issued June 17, 1930, also to P. Artigue, the main point
of interest relating to the mounting of the glass and miniature on a
staging with the camera so as to permit the two to be moved about
as for panoramic views, without disturbing the relation of the glass
to the camera. In view of the many devices for movable cameras
with all sorts of attachments, a question may be raised whether such
a system as here disclosed involves invention.
GLASS SHOTS BY REFLECTION
One worker in the field, Eugene Schiifftan, has concentrated on a
variant of the ''glass shot," in which is employed a glass plate, partly
reflecting, partly transmitting, that seems to have been developed to
a substantial degree of completion. In each instance he uses a glass
plate that is partly silvered, but has unsilvered transparent portions.
This glass is placed before the camera lens, the camera beam being
divided so as to bring light upon the film from two subjects.
The first of his patents, No. 1,569,789, issued January 12, 1926,
discloses a mirror partly silvered over an area of the camera field of
view in which the action is to occur, and unsilvered over an area of
the field of view in which a miniature set is to appear. The action
is then viewed by reflection, and the miniature set is viewed by trans-
mission through the glass. The reverse procedure is, of course,
April, 1933] COMPOSITE PHOTOGRAPHIC PROCESSES 299
possible. Various details are outlined, such as an adjustable seg-
mental mirror, etc.
His second patent, No. 1,601,886, issued October 5, 1926, deals
mainly with the mechanical equipment for the process. It includes
such items as a small projected background, a supplemental collecting
lens to correct the focus on the miniature, mechanical details of the
camera and miniature, etc.
Two other patents, Nos. 1,606,482-3, issued on November 9, 1926,
furnish still other details of the process and apparatus, including the
method of operating it, of preparing the mirror and the miniature
drawing, registration, blending, etc.
Another patent, No. 1,613,201, issued January 4, 1927, discloses
a special double-lens camera, which is combined with a considerable
number of partly silvered mirrors for assembling a plurality of sepa-
rate picture elements. This idea is extended in a somewhat better
mechanical form in patent No. 1,627,295, issued May 3, 1927.
Still another of this group of patents, No. 1,636,112, issued July
19, 1927, shows and claims the details of a large collecting lens in
combination with the mirror, for modifying the effective focus of the
camera lens on the reflected image, bringing both reflected and trans-
mitted light beams to an equally sharp focus.
The last of this group of patents to be considered is No. 1,690,039,
issued October 30, 1928. This is a division of an earlier application,
issued as patent No. 1,569,789, and discloses and claims the pro-
jection of a miniature upon a translucent screen, in combination with
the partly silvered mirror, camera, and full-scale scenery and actors.
SELF-MASKING PROCESSES
In any composite process the most troublesome problem is that of
accurately registering the respective composited parts, the problem
being most acute in traveling mask processes, and least acute in the
color-separation processes. Because of the convenience of mask
processes, attempts have been made to develop what may be called a
"self -masking" process.
The first of these, as previously mentioned, is shown in patent No.
1,503,731, issued to J. B. Walker, on August 5, 1924. Walker pro-
poses to swell the gelatin film so as to obtain a relief image of the fore-
ground or action exposure, after development, but before fixing. A
coat of ink or dye is then applied to the raised portions (the action
may be photographed before a non-actinic screen for background).
300 H. D. HlNELINE
The film is then dried, reexposed on the other component, redeveloped,
etc., and the ink removed. Obviously, success depends upon inking
only the foreground, and all of it.
The next similar suggestion is found in Patent No. 1,697,315,
issued January 1, 1929, to M. Handschiegl. This patent proposes a
process of photographing action on film that is not color-sensitive,
developing, and printing the unfixed film on panchromatic stock by
red light. A second print, made from this print, forms a mask to
protect the first exposure while a second is added, after which a
second development, etc., yields the composite negative. This is not
quite a self -masking process, but is of interest for the double develop-
ment.
M. Osann suggests, in Patent No. 1,698,448, January 8, 1929,
toning a developed but unfixed film of the foreground, photographed
before a non-actinic screen, to increase the opacity of the image. He
uses a cupric ferrocyanide toner for the more light absorbent red
image. A second exposure is made over the toned image, developed,
etc., for the background. Panchromatic print film with the negative
is suggested, probably to avoid the density unbalance between the
two images. A simpler way might be to tone the second image.
R. J. Pomeroy, in Patent No. 1,755,129, April 15, 1930, suggests a
similar process, toning the first image with a quinone toner, reexposing
etc., the toning being removed by the fixing bath. He also suggests
a selective desensitization as by phenosafranine, to protect the first
image area. He also suggests, in Patent No. 1,755,130, same date,
a pigmented casein coating, applied to the film after foreground
development. Bleaching then hardens both the film and casein
coating over the image, the rest being removed, producing a self -mask,
over which the second exposure is made, developed, etc., and the
casein coating removed by mild caustic.
This assortment of processes should provide one, at least, which is
usable under any given circumstances, although each has its limita-
tions. It should also be noted that most of the above-mentioned
patents are still in force. For further information on the processes
described, copies of the patents may be obtained from the Com-
missioner of Patents, Washington, D. C.
THE OPTICAL-PHOTOGRAPHIC PRINCIPLES OF THE
AGFACOLOR PROCESS*
F. WEIL
Summary. — The physical and photographic properties of the lenticular screen
process of producing motion pictures in color, as developed by Berthon, and later
known under the name Keller-Dorian and commercialized in the 16-mm. field under
the name Kodacolor, are briefly described. The author traces the development of
the process from the earlier mosaic screen process, and after giving consideration to
the technical problems involved, indicates that the situation obtaining at present
may be regarded as one stage of a development leading up to the application of the
lenticular screen process to the 35-mm. field as well as the 16-mm. field.
Processes of making motion pictures in natural colors must satisfy
at least the following principal requirements in order to be technically
and practically successful:
(1) The photographic manipulation and apparatus must be simple.
(2) The process must provide sufficient color saturation and resolution;
that is, the color elements must be small enough to be unobjectionable.
(3) It must be possible to make prints from an original exposure.
(4) The process must make efficient use of the available light, both in making
camera exposures and in projecting the pictures on the screen.
It would be impossible, within a limited space, to mention all
the processes that have been suggested and tested, or are still in the
experimental stage, for producing colored motion pictures. A re-
view of present methods is given by J. Eggert.1
This paper describes briefly the physical and photographic princi-
ples of the lenticular screen process as developed by the French
optician, A. Berthon, in 1908. In 1913, Berthon and Keller-Dorian
formed the "Societe anonyme du film en couleur Keller-Dorian;"
and, under the name of Keller-Dorian, this process is widely known.
Out of this company, the "Societe Cinechromatique" was formed in
France, while Kodak took over the patents and commercially
applied the lenticular screen process to 16-mm. film under the name
* Translated from Filmtechnik, 8 (Sept. 3, 1932), p. 1.
301
302 F. WEIL [j. S. M. P. E.
of Kodacolor. Recently, Agfa has also produced a 16-mm. film based
on the same principles, called Agfacolor.
Up to the present time, both companies have restricted themselves
to the production of 16-mm. film only. The amateur usually takes
his pictures outdoors, where he finds a large variety of colors and a
wide range of light intensity; the lenses of amateur movie cameras
have sufficient focal depth even at large apertures. Moreover, the
lenticular screen process is so simple that only small and easily
adaptable accessories are required in order to apply it to any existing
camera. As to the photography, there is no difference between this
process and the reversal process generally used in 16-mm. film technic.
Therefore, the technical development of this field has not been re-
tarded by unsolved problems of a satisfactory printing process.
The 16-mm. picture is projected only to a limited size and brilliancy
on the screen.
The fact, however, that this process is being applied only to 16-mm.
film should not lead to the conclusion that it can not be applied to
the 35-mm. standard motion picture film. The situation at present
may be regarded as one stage of a development leading to the
application of the lenticular screen process to the 35-mm. field as
well.
In certain respects, the lenticular screen process in its photo-
graphic and optical principles is an extension of the mosaic screen
process, long ago introduced into amateur photography. Indeed
it might be regarded as a color screen process modified for motion
picture purposes. Both the lenticular and mosaic screen processes
are so-called additive processes ; that is to say, the required colors are
produced by blending three primary colors. A combination of red and
green produces yellow; red and blue produce purple; blue and green
produce bluish green. Red, blue, and green when properly com-
bined, produce white. Conversely, it is possible to analyze any given
color, with respect to the proportion of red, green or blue contained
in it, simply by using filters of these colors. The color may then be
reproduced by mixing light of these colors in the same proportions.
This separation, or analysis, of the color can be accomplished photo-
graphically by exposing the film to the object through the color
filters, either simultaneously or in succession, using one or several
lenses. For reproduction, these exposures must be optically super-
imposed in perfect registration. With a color screen or lenticular
screen, however, the tri-color analysis can be made in a single ex-
April, 1933] PRINCIPLES OF AGFACOLOR PROCESS 303
posure, by dividing the photographic coating, in one way or another,
into numerous small units, each unit being fitted with a red, green,
and blue filter. The smaller the units, the higher the resolving
power. Theoretically, these units should not be so large as to come
within the resolving power of the eye (visual angle of 1 minute,
corresponding to about 0.02 mm. at the natural viewing distance).
Each area is fitted with a composite tri-colored window through
which the light from each individual area of the object passes to the
emulsion coating.
In the mosaic screen process we find the simplest application of
this principle. Between the emulsion coating and the film (or glass),
we find the color screen, an even blending of red, green, and blue
transparent grains of starch or bakelite, irregularly dispersed. The
mixture of the grains is never quite uniform, as the formation of
small clumps of grains can not be avoided. The exposure of the
emulsion is always made through the screen. Each group of differ-
ently colored grains forms a screen unit, in the sense already ex-
plained, and the light rays, passing through the grains, produce a
photographic effect according to the primary-color content of the
rays. In order to see the original in its true colors, it is necessary
to subject the developed film to a reversal process, because the usual
negative development produces only the complementary colors.
Unfortunately, the mosaic process can not be used for motion
pictures. First of all, the enlargement necessary for motion pictures
would magnify the grains of the color screen to a size within the
resolving power of the eye, thus making the individual grains visible.
Furthermore, on account of the random distribution of the color
grains, local aggregations of similarly colored grains can not be
avoided. A greater difficulty, however, is the fact that the random
distribution of the screen elements over the entire image surface —
their positions relative to the perforations of the film — changes with
each and every frame of the film. On account of the intermittency of
projection, these two effects cause a violent irregular movement of
the colored grains, producing a disturbing visible effect particularly
on larger areas of uniform color.
In order to adapt the color screen process to motion pictures,
it would be necessary to arrange the color elements in a regular
pattern parallel to the edges of the film. Thus the elements would no
longer be distributed haphazardly. Naturally, the manufacture of
such an extremely fine screen involves many practical difficulties;
304 F. WEIL [j. s. M. P. E.
nevertheless, commercial experimentation has already been successful
and is being continued.2
The lenticular screen process as developed by Berthon solved the
problem by very simple and ingenious means. Berthon abandoned
from the very beginning the idea of attaching the niters, correspond-
ing to the different surface elements, to the film, and of providing the
film itself with a real color screen. On the contrary, the screen is
produced on the film optically during the exposure, and on the screen
during projection. The film serves only as a support for an optical
system of tiny cylindrical lenses embossed on the film base. The
width of each lens is about 0.028 to 0.043 mm., the focal length being
0.1 to 0.14 mm. The lenticular screen is adjusted to the taking or
projecting lens system, as shown in Fig. 1. A color filter having
three colored areas — red, green, and blue — in three parallel sections,
is placed either inside or outside the lens system. It does not matter
where the filter is placed, so long as it controls the aperture. Further-
more, the filter diaphragm, or its virtual image, must not obscure
the entrance pupil of the lens from any part of the film. The outer
parts of the filter would be so obscured, viewed from the margins
of the film area. This defect will be more fully described later.
Once the position of the filter has been fixed for exposing the film,
this position becomes an inseparable characteristic of that particular
film, and controls the true color reproduction. The illustration
shows the color filter (e,g,r) placed in front of the lens, as occurs in
practice. Its virtual image appears at a distance F from the film,
the width D representing the limiting diaphragm. Each of the
cylindrical lenses embossed on the film produces a real, inverted,
and reduced image of the tri-color filter in the focal plane of the
embossed lenses, since the distance from the film to the filter, in
comparison with the very short focal length of the embossed lenses,
is practically infinite. The filter images replace the grains of the
mosaic screen, each image corresponding to one of the previously
mentioned screen units. The maximum width is equal to the width
of one embossed lens, and its length extends over the entire height
of each picture, in the direction of the axis of the cylindrical lens.
However, the units do not carry their own real three-color screens,
but look, so to speak, through telescopes to the one common color
screen, placed in the limiting diaphragm of the lens. The film itself
appears colorless under ordinary observation.
The development is the same as in the color screen process; i. e.
April, 1933]
PRINCIPLES OF AGFACOLOR PROCESS
305
the original must be developed to a positive in order to obtain a
direct reproduction in true colors. But while the color screen positive
itself contains all colors, it is necessary to provide certain optical
arrangements for projecting the lenticular films in true colors.
This is not of particular advantage in motion picture work. The
simplest arrangement would be to use for projection the same lens
FIG. 1. Diagram of the optical system of the Agfa-
color process. The cross-section of the film itself is shown
at a much greater magnification than the objective and
filters.
as used in the camera which would simply reverse the path of the
exposing light. When lenses of other focal length and construction
are used, care must be taken that the position and width of the color
filter appear, from the point of view of the lenticular screen, identical
to their relations during exposure. It is only then that, at the given
focal length of the lenticular elements, the position and width of the
306 F. WEIL [j. s. M. P. E.
filter images behind the lenticular screen are identical to those of
silver images formed by exposure and development of the film.
If the color value of the projected image is to be at its best, the
screen must satisfy certain requirements :
(1) The real image of the filter as projected behind the lens ele-
ments must lie in the optical plane of the emulsion; the thickness
of the film base and the focal length of the lens elements depend on
each other. The focal length of the lenses, in turn, depends on the
refractive index of the base and on the curvature of the lenses ; hence
the embossing of the screen must be done in a very particular way.
(2) The real filter images behind the screen should cover the
aperture of the lens element in the same way as the filter covers the
aperture of the camera lens. No light should be allowed to pass be-
tween the filter images, as the white light thus passing would weaken
the color. The size of the real filter image behind the screen is de-
termined by the following simple optical relation: If, according to
Fig. 1, D is the apparent width of the filter, as viewed from the
film, and F is the apparent distance of the filter, then F/D will be the
aperture at which the filter appears when viewed from the film.
If we call F' the focal length of the screen lenses, d the width of
the real filter image, and n the refractive index of the film base, the
following equation will result:
?L n F
T=:^D"
If the ratio F/D is given by the focal length of the lens and the
arrangement of the filter, then the maximum focal length of the lens
elements is limited, as the width of the filter image can not be greater
than the width of the cylindrical lens elements; or, by using a tri-
color filter, the adjoining images on the outer filter strip would over-
lap, and red and blue colors would appear more or less purple.
(3) The narrower the individual screen lenses, the less the striped
screen of the image will be visible on projection ; on the other hand,
the resolving power increases, and enables even the smallest images
to be resolved into their details. Naturally, the grains of the emul-
sion should be small compared with the width of the stripes of the
filter image. In the Agfacolor process, in which the width of the
lenticular elements is 0.028 mm., the images of the individual color
stripes have a maximum width of 0.009 mm., or twenty times that of
the wavelength of green light. With respect to resolving power,
the lenticular screen is superior to the mosaic color screen. Owing
April, 1933] PRINCIPLES OF AGFACOLOR PROCESS 307
to the geometrical coordination of the object, lens, screen, and image,
details even smaller than the width of the lenses are reproduced in
their correct position as regards color. With images smaller than
one-thini the width of the screen, mixed color details can not be
resolved into their individual color elements.
(4) The quality of the pictures depends largely on the photo-
graphic qualities of the emulsion; particularly, on its color sensi-
tivity. The latter, in turn, determines the choice of the filter colors
with respect to their spectral transmission. The judgment and
decision on this matter and the choice of the filter combination
must be based merely on the principles of subjective psychology
and on the average taste.
Theoretically, the lenticular films can be printed, but not by the
ordinary contact method — numerous possibilities of doing this
have been described and patented. It is important to preserve
the original coordination between the density and the lens elements.
The geometrical coordination between the silver grain, the lens
elements, and the projection lens must be identical in both the copy
and the original.
From the above it is seen that the characteristics of the lenticular
film depend on the fact that the film itself bears the optical system
that makes reproduction in colors possible. The quality of the pro-
jected picture depends a great deal on the degree of perfection of the
screen. Consequently, processing, storing, and projecting require
special attention. Grease spots, for instance, frequently encountered
in motion picture theater practice, will change the optical properties
of the screen or are likely to cause the entire screen picture to dis-
appear.
As a support for an optical system, the entire area of the film must
lie in proper relation to the lens and filter in both exposure and pro-
jection. Kinks or similar mechanical defects cause color distortions
in projection. In addition to this, an exact adjustment of the camera
or projection lens with regard to the film is very necessary. If, for
instance, the projector aperture is not vertical to the optical axis
of the lens, or if the film does not lie flat in the projector aperture,
untrue colors will appear at the edges — so-called color dominants.
Excessive drying of the film, which always causes some loss of sol-
vents, also causes some displacement of the lens elements and is
likely to disturb the projection. It is, therefore, advisable alway
to store the film in air-tight cans.
308 F. WEIL
With regard to transmission of light by the lenticular optical
system, since the tri-color analysis is made with only one lens (for
instance, a red surface would, when exposed and projected, use only
one- third of the aperture; and, since the colors of the filters are not
pure spectral colors, but contain some gray), there is greater loss
of light in this process than in ordinary black-and-white photog-
raphy. However, in motion picture photography, using lenses of
short focal length and greater depth of focus, larger apertures can
be used. The maximum usable width of the aperture is limited by
the effective area of the lens in which there is no vignetting. If the
filter were larger, parts of the lens mounting, or their virtual images,
would obscure portions of the filter. This partial loss of one color
would cause color dominants to appear at the edges of the picture
when projected. For the same reason, it is impossible to use an
iris diaphragm in order to reduce the amount of light. It is necessary
to use neutral density filters (Eastman) or detachable slit diaphragms
(Agfa). For exposure, lenses with relative apertures less than
//2.0 are hardly to be considered. The loss of light caused by the
optical system can, to a certain degree, be compensated for by in-
creasing the photographic sensitivity of the film. As the situation is
at present, lenticular film can be used for outdoor exposures even under
an overcast sky, and, under favorable lighting conditions, indoors.
Satisfactory projection can be obtained only with powerful pro-
jectors. Because of the loss of light, mentioned before, and for
psychological reasons, it is necessary to have maximum brightness
for color projection.
Before lenticular film can be introduced into motion picture
theaters, some technical (not fundamental) difficulties must be
overcome. First, it must be possible to make prints; second, the
screen brightness must be sufficient. The requirements regarding
illumination in the studio can be satisfied by increasing the sensitivity
of the photographic emulsion. It is, however, difficult to solve the
problem of obtaining satisfactory illumination on the large screens
used in motion picture theaters.
REFERENCES
1 EGGERT, J.: "A Resume of the Status of Color Cinematography," VIII.
Internat. Kongress fur wissenschaftliche und angewandte Photographic, /. A.
Barth, Leipzig, 1932, p. 214.
2 BAKER, T. THORNE: "The Spicer-Dufay Process of Color Cinematography,"
VIII. Internat. Kongress fur wissenschaftliche und angewandte Photographic,
/. A. Barth, Leipzig, 1932, p. 230.
THE PRODUCTION OF ANIMATED CARTOONS*
WILLIAM GARITY**
Summary — This paper describes the general procedure employed in producing
animated cartoons, particularly the technic employed by the Walt Disney Studios.
The qualities required in the animators, and the problems that these animators must
solve in realizing the dramatic situations and synchronizing them with the music
and sound effects are discussed. An example of the procedure followed in producing
the cartoon is given, including illustrations of the layout sheet, exposure sheet, and
camera field charts.
The method followed in producing a sound cartoon is basically
simple. The degree of its success depends almost entirely upon the
care and attention given to detail. The picture is built up frame by
frame, and any tendency to overlook detail is reflected in the finished
product. When one realizes that ten to fifteen thousand individual
drawings are required for each complete production, it becomes clear
why such great care must be exercised by all the production de-
partments.
This company produces two series of cartoons, the Mickey Mouse
and the Silly Symphonies. This year, the program calls for the
production of a total of twenty-six cartoons, eighteen of which are to
be Mickey Mouse, and eight Silly Symphonies. All the Silly Sym-
phonies are to be released in "Technicolor."
In the Mickey Mouse cartoons, it has been the endeavor to build
up definite personalities, not only of Mickey and Minnie, but of
all the supporting characters as well. Every effort is made to main-
tain the same personality of each character in each picture, so as to
establish that character in the mind of the public.
The Silly Symphonies are entirely free from any such limitation,
and wide latitude is possible in selecting the subjects. It is the
present intent to maintain this series in the realm of the unreal.
The spirit of the seasons has been expressed in the subjects entitled
* Presented at a meeting of the Pacific Coast Section, Dec. 14, 1932.
** Walt Disney Studios, Hollywood, Calif.
309
310 WILLIAM GARITY [j. s. M. P. E.
Springtime, Summer, Autumn, and Winter; in others, the themes
have been drawn from the fairy tales of old.
The principal difference between producing live-action subjects
and animated cartoons lies in the fact that in live action, it is possible
to rehearse the characters, see the immediate results, and select the
best of several takes for the final product. In producing a cartoon,
the director must visualize his action in terms of pen lines, plan his
entire continuity, entrances and exits, dissolves and cuts; in other
words, do all his editing, before a single picture is drawn. His only
recourse, when his picture is finished, is to eliminate scenes. But it is
not always possible to do this, because a recorded musical score is
not as flexible as we sometimes wish it were.
In producing cartoons, it is necessary to analyze the story and
break it down into several scenes, and to distribute these scenes
among many individual animators. This requires that all the artists
adopt a standard style of drawing, a difficult matter for an artist
when he is entering the cartoon business. He must change his style
to conform to the requirements of production. This is particularly
difficult for an artist who has been developing his own individual
style for any length of time.
Three types of men to be found in the cartoon business are: the
artist, the animator, and the artist-animator. There are many men
of artistic ability who find it impossible to create animated cartoons.
There are also those who can animate, who can produce good action,
but whose artistic ability is mediocre. The third group comprises
the artist-animators, who combine the qualities of the other two
groups.
Experienced men in this field are few and it is necessary, therefore,
to maintain a group of apprentices of little or no production value,
and to train them in the art of animation so as to be able to develop
the organization. These apprentices are required to attend art
classes at the studio. The period of apprenticeship lasts for about
six months, never less, and often longer.
Very few men qualify in all branches of art. Some excel in char-
acterization; others in mechanical action; others are particularly
gifted in animating dialog; others have the ability to give subtle
touches to action. They are all classified as to their ability, and
as far as possible, are given those parts of the work for which their
particular talents are best adapted. Considering the fact that an
artist-animator can with diligence produce only five feet of action
April, 1933] ANIMATED CARTOONS 311
every eight hours, it is necessary to conserve his time by assigning
to him the kind of work he is able to do best.
In producing a cartoon, the first consideration is the story. If
the story is good the results are usually gratifying. The finest
music, the best sound recording and the most expert camera work,
will never make a success of a cartoon with a poor story. As in live
action, the director plays an important part in cartoon production.
It is his function to present the story so as to make the most of its
strong points and bolster the weak ones. He must visualize the
action, build up the situations, and time the action so that nothing
is lost. The selection of music and sound effects is his responsi-
bility; and he must supervise the work of each animator in order
that his ideas be carried out, in addition to supervising the recording
of the music and effects. On him, as in live action, rests the responsi-
bility of the picture as a whole. Next in importance are gags and
situations.
Following in the order of importance, are the musical score and
sound effects. The music must fit the mood of the picture in order to
be effective: if properly chosen, it enhances the value of the story
and the action; if improperly handled, it annoys and detracts.
In the same way, certain sounds are effective in some situations,
whereas the same sound in a different situation would be discordant
and annoying. Sound effects should be adapted to the action;
a sound effect should never be used unless the eye is conscious of the
source of the sound.
The last items in consideration of a good subject are technical
perfection, camera work, and sound quality. While we place these
items last in importance, they are the ones that cause us the greatest
trouble and require constant supervision.
The synchronization of sound to the cartoon is probably responsi-
ble, to some degree at least, for their success in the field. This one
phase of producing cartoons is probably the least understood by the
public, although it is perhaps the simplest part of the problem.
Since the advent of talking pictures and the standardization of film
speed, the problem became simply one of resolving all musical
tempos in terms of the standard speed, and of making a consecutive
series of drawings to fit this tempo. In order to do this, certain
basic tempos, multiples of the frame speed of the film, have been
established. For example, the fastest tempo employed is one beat
every six frames, amounting to four beats per second. The total
312 WILLIAM GARITY [j. s. M. P. E.
range is from this to one beat every twenty frames, or one beat every
Veths of a second.
The Story Department presents the most difficult of all the pro-
duction problems. When one realizes that a picture must be re-
leased every fourteen days, the reason is quite obvious. The men in
this department work continuously, developing material for pictures.
The first step in the production of a cartoon takes the form of a rough
draft of a story prepared by the Story Department. The following
is an abstract of such a story outline :
United Artists Symphony No. 7, Santa's Workshop; Jackson, director; Church-
ill, music.
Story opens showing exterior of Santa's workshop at the North Pole — beautiful
scene, snow falling, etc., Santa's factory buildings.
Dissolve into an exterior of Santa's stables; little gnomes busily grooming the
reindeer, washing their teeth, etc.; all busy and whistling, or some other musical
effect.
This dissolves to the interior of the workshop, showing happy gnomes busily
operating the quaint machinery ; all gnomes whistle as they work. Show various
closeups of individual elves making toys. Everything is run in the manner of the
Ford factory. (Plenty of opportunities here for showing the ludicrous methods
used by the gnomes in making the toys.)
Santa is the big boss who "okays" all the toys. He is happy and very good
natured, and gets a big kick out of the various things the toys do. Santa could
teach the dolls to speak and say "mama."
Amusing action of toys of various kinds, walking in their own individual ways.
The toy band strikes up a snappy march and all join in a big procession leading
to Santa's bag. When all the toys enter the bag, Santa picks it up, puts it into his
sleigh, and drives off. Make a beautiful final scene, Santa disappearing in the
sky in the distance, all the elves singing a Christmas song; just before the iris
closes, show a silhouette effect of his reindeer and sleigh as they cross the Christ-
mas moon, the voices of the elves coming in full volume for a final finish effect
on the end title.
Everyone think this over and have some good "gags" ready to hand in at the
next gag meeting. I expect a big turnout on this story. "Walt."
This story outline is mimeographed and handed to all the ani-
mators at a gag meeting. These gag meetings are held every two
weeks for the purpose of discussing future pictures. The discussion
is held within the limits set by the Story Department, outlined as
above. Two weeks following the discussion of the story, the ani-
mators hand to the Story Department suggested gags and situations
for the particular story. The Story Department then makes a
complete study of the submitted gags and situations, and prepares a
definite story outline in the form of a scenario. Then a conference
April, 1933]
ANIMATED CARTOONS
313
is held with the director and the musician, who are to produce the
picture, at which the director is made acquainted with the story
and assisted in preparing the continuity so as to preserve the original
ideas and situations.
In this conference is included the "set designer," known as the
"layout man." It is his function to prepare rough sketches of the
complete scenes, depicting the atmosphere of the action, keeping
in mind the movement of the characters. From these sketches, the
background sketches are prepared and, finally, the finished back-
grounds. In making the backgrounds, it is necessary to leave clear
<J?C2 yt~
?Q3 fa/or/<&hof?
| MAnKiTVTte (
^) ^>«/y
^° ^"/v^W% OM/V /^y"
— f¥
CHoRu-3— %
1 f 1 1
'i ; i — r
5"
7
-
ii^t^r^^ ^— -^
/^f5/C -f */Hj9f£l'lH& SdfT rtA*Y fflff r/t/e"»
9
X
X
VWtStlalwfc 3oFT-
SETS
H
o I- —
ir
•£S>
>
3.0
0
3l
[X
J V
^^ ^^^&j&&4jil££j&jl£t * *° ^ ^ ^
Lj5^^ ^AINT FOT
x s-
2V
So
3i
3A
3CS(H GMO«JE5^69^«6)
30-5 GR21tV««°1tlw>S,.Ti«
tfai^-VH
—
•2
JC--
^>^
• 3,,
^^
.^^__
FIG. 1. Layout sheet used for planning the picture.
such portions as will later be occupied by the animated figures.
The layout man must assist the director in maintaining good con-
tinuity of background, so that when camera angles are changed,
the resulting background change will be smooth.
The director and the musician, at the end of this conference,
have a very definite idea of the story, situations, and gags to be
used; and the approximate footage of film that will be needed.
The story is then laid out on a layout sheet, shown in Fig. 1. Each
"box" (or small rectangle) represents a bar of music. How much of
the picture is to be shown during each bar depends on the tempo
314
WILLIAM GARITY
[J. S. M. P. E.
at which the music is to be played. Referring to Fig. 1, each box,
starting at 1, covers 48 frames of action, the tempo being indicated
as 4-12. While working on the sheet, the musical director writes
his preliminary master score. In some cases, when it is desired to use
a certain piece of music, the director is required to adapt the action
to the music. At other times, the action requires entire freedom
from musical limitations, except with respect to tempo. In this
case, the musician must compose music to suit the action. It is by
means of the layout sheet that the entire problem is resolved, the
action made to suit the music, and the music written to suit the action.
TITLE OF PRODUCTION
-2-
PICTURE No.
STARTED
"SANTA''S iVORK SHOP"
U.S. # 7
COMPLETED
FOOTAGE
•sr
A«T,.T
DATE
DATE
INSCRIPTION OF ACTION
14-10
24
BEN
M.C.U. PERMANENT i/AVE.
4-14
25
KING
M.C.U.
iANTA PICKS UP MAMMA DOLL
15-6
26
•
S.A.25
g£j{. TEACHES COLL TO SAY "MAMMA" O.K.1
37-2
27
•
S.A. 25
M.C.U. SANTA INSPECTS MAMMY DOLL AND
AIRPLANE.
7-4
28
BEN
M.C.U. PLANS KNOCKS TOYS OFF SHSLF.
11-14
29
„
L.S. TOYS START TO MOVE.
18-6
35-10
12-
30
•
PAH
M.L.S. BAND AND SOLDIERS KARCH.
51
,
PAN
M.C.U. VARIOUS
TOYS IN PARADE.
32
GERRY
M.L.S. TOYS START INTO BAG (TRUCK)
FIG. 2. A production schedule.
The director and the musician work hand in hand, measure by
measure, frame by frame; each one trying to adjust his particular
problem to meet the demands of the story.
When the layout sheet is completed, the director has his picture
completely laid out to the frame, and the musician his master score
to the note. Slight changes may later be made in order to accommo-
date the exigencies that may arise when the pictures are animated.
It is everyone's desire to preserve the layout sheet as final, but
necessity requires that it remain flexible.
The production schedule shown in Fig. 2 is next prepared. As
will be noted, this schedule contains the scene numbers, the footage
April, 1933]
ANIMATED CARTOONS
315
of the scene, the name of the artist, and a description of the action to
take place : scene 24, the first scene on the sheet, is allocated a footage
of 14 feet, 10 frames to be drawn by the artist, Ben, and to be a
medium close-up showing a permanent wave. As soon as the schedule
is completed, the director fills out an exposure sheet, shown in Fig. 3,
describing in terms of frames of picture the continuity of the action,
exactly on what frame the sound effects will occur, and what the
nature of the sound will be. The tempo of the action is also shown on
=^^—
Lftj
T3e.-ri
U.S '7
IS-/C
s
PAN •
CAMERA
TO H
FIGLP
AT
PER X
Slf
u
T
FIG. 3. Exposure sheet completely filled out, showing instructions
for cameraman.
the exposure sheet. This exposure sheet is prepared with the assis-
tance of the musician, who simultaneously marks on his master music
score the exact position of sound effects.
The director, when preparing the exposure sheet, definitely in-
structs the animator as to the nature of the scene to be depicted,
the exact footage that the scene should occupy, and the tempo of the
music to be played during that particular sequence. The director
also explains to the animator in great detail the relation of his se-
quence to the rest of the story, points out the particular gags or
situations that are to be developed, and supplies the animator
316 WILLIAM GARITY [j. s. M. P. E.
with the necessary information concerning the preceding and suc-
ceeding scenes. The animator is also furnished with a background
sketch which serves as his stage setting. It is the animator's function
to visualize the scene in terms of pen-and-ink lines, and to produce a
series of progressive drawings of the scene that will tell the story
and the ideas incidental to it. The animator is quite limited, due
to the fact that the musical tempo, as well as the footage of the
scene, is fixed. He will sometimes find it necessary to shorten or to
extend his bit of action to complete his sequences more effectively.
In this case, he confers with the director; and if the latter approve
such a change, the musician is consulted, who must rearrange the
score to suit the change of footage. Such a procedure is avoided
as much as possible, for obvious reasons.
As the animator makes his progressive drawings, he numbers
them serially, recording them at the same time in the columns pro-
vided on the exposure sheet, in the order in which they are later to
be photographed. The animator confines his drawings to a field
approximately seven by nine inches. At the lower edge of the drawing
paper outside the field are two perforated holes. These control
the registration of the drawings. The animator's drawing board is
provided with an insert of glass, under which is placed an electric
light. On the edge of the glass insert nearest the animator, on the
top surface of the drawing board, is placed a bar containing the
registering pins, on which the paper is fastened. All drawings, in-
cluding backgrounds, are made only when the paper is engaged by
these pins. The paper used has a hard finish, and is very light in
weight, so that tracing of images is facilitated.
Each animator has an "in-between" man or an assistant, and
generally two apprentices. In order to conserve the animator's
time, he makes drawings of only the extreme action, and makes a
finished model as a guide for his assistants, who fill in the intervening
drawings. For example: if the action require a walking character,
taking 16 frames for a complete step, the animator makes drawings
Nos. 1, 8, and 15, his assistant, or in-between man, making drawings
Nos. 2 to 7, inclusive, and 9 to 14, inclusive. The assistant then hands
the drawings to the apprentices, who fill in all the necessary detail.
When the animator has completed his particular scene, the
drawings are turned over to the Inking and Painting Department,
the function of which is to transfer or trace each drawing on celluloid
sheets. These celluloid sheets are the approximate size of the paper,
April, 1933] ANIMATED CARTOONS 317
and about 5/i0ooths of an inch in thickness. They are perforated with
registering holes, identical to those in the drawing paper. The paper
drawings are placed on the registering pins, the celluloid sheet is
superimposed on the drawing, and a very careful tracing of the draw-
ing is made with black India ink. After the tracing of the outline
has dried, the celluloid is reversed, and the entire area occupied by
the figures on the drawings is made opaque with paint.
The primary reason for using celluloids is an economic one. If
the transparency were not used, it would be necessary to draw a
complete background for each frame of the picture, which, of course,
would be an economic impossibility. To avoid doing this, a single
background is drawn, the characters working against this background
being traced on the celluloid sheets. As the entire area occupied by
the character is rendered opaque, the background is completely
matted out by the character when the celluloid sheets, inked and
painted, are superimposed on the background. It is possible to
have a large number of characters, each doing something different,
by tracing each character on a separate sheet of celluloid, and simul-
taneously superimposing these celluloid sheets upon the background.
The use of many such celluloid sheets aggravates the photographic
problems, due to the light losses and color changes introduced by the
celluloid. Four sheets seem to be the greatest number that may be
used without seriously affecting the photography.
For rendering the celluloid sheets opaque, white, black, and
five shades of gray paint are used. When a number of characters are
superimposed simultaneously on the background, 1, 2, 3, or 4 sheets
of celluloid are used. In order to produce the same color value in the
negative, five different shades of gray paint must be employed.
The darkest shade is used on the top sheet and the lightest on the
background. This is necessary because of transmission losses inherent
to the celluloid. The thickness of the sheet is also a factor to be con-
sidered; and for that reason all sheets are carefully graded as to
thickness and color, in order to minimize the painting problems and
reduce density changes in the half-tones of the film.
After the picture is photographed, all traces of the ink lines and
of the paint are removed by washing, thus reclaiming the sheets for
later use. In practice, the celluloid sheets are never used more than
three times, due to the fact that the surfaces become badly scratched
and marred when used more often. Also, after the third time, the
celluloid becomes discolored, an effect impossible to control by
318
WILLIAM GARITY
[J. S. M. P. E.
means of the paint. Also, as the celluloid ages, shrinkage becomes a
serious factor, preventing the sheets from fitting properly over the
registering pins.
After the celluloid sheets are completed by the Painting Depart-
ment, they are turned over to the Camera Department for photo-
graphing. A standard Bell & Howell camera is employed, equipped
with a stop-motion mechanism driven by a synchronous motor.
The camera can be moved vertically to change the size of the field,
as well as from right to left (east and west), fore and aft (north and
FIG. 4. Camera field chart; used for orienting the optical center of the
camera.
south), and rotated through an arc of 360 degrees. The optical center
of the camera is oriented by means of a "camera field chart," shown in
Fig. 4. A copy of this chart is in the hands of each animator. The
calibration of this chart is identical to that of the scales on the camera.
Fig. 5 shows a photograph of the cartoon camera and camera stand.
The celluloid sheets representing the action of a single frame
of the picture are assembled and placed over the background of the
scene. The "eels" are held in position by registering p'ins. An
optical glass plate flattens the "eels" against the background, thus
April, 1933]
ANIMATED CARTOONS
319
removing any wrinkles or curl. The glass plate is operated by a
compressed air mechanism.
If less than four "eels" are required for the action, blank "eels"
are added so as to preserve the photographic values of the back-
ground. Four "eels" are always used between the camera and the
background. The camera operator follows the instructions outlined
on the exposure sheet. A completed exposure sheet is shown in Fig. 3.
FIG. 5. Cartoon camera in camera stand.
Approximately 100 hours are required to photograph a cartoon
subject, which averages about 600 feet of film. If the subject should
contain more than the usual number of so-called "trick" shots,
which may require complete camera readjustment for each frame of
film, the shooting time will easily run from 125 to 150 hours.
During the time consumed in animating, inking, and photo-
320
WILLIAM GARITY
[J. S. M. P. E.
graphing the picture, the musical score is completed and arranged,
and the sound record is made. It is not necessary for the purpose of
scoring to see the picture. As the musical score is prepared in ac-
cordance with the same tempos as those used in drawing the pictures,
the musical director knows exactly at what frame in the picture
every musical note or sound effect will occur.
Not only are parts written for all the instruments in the orchestra,
FIG. 6. Recording a Mickey Mouse cartoon; trap drummer's table in center.
Note the head-phones used by each member of the orchestra.
but each trap drummer, or effect man, is supplied with a score that is
as complete in detail as is the part for the first violin. The position
of the effects is written on the score as musical notes, postscripts
being added to describe the kind of sound or effect required. The
trap drummer must be able to read music and to assign proper
values to the sounds as indicated by the musical notations.
Each member of the orchestra, as well as the conductor, is provided
with a head-phone (see Fig. 6) similar to that used by telephone
operators, in which is heard the tempo of the music to be played.
This beat is developed by means of an audio -frequency oscillator
April, 1933] ANIMATED CARTOONS 321
controlled by a synchronously driven contacting device, which makes
and breaks contacts in terms of frames of synchronously running
film. Experience has shown, after trying perhaps every known
method of achieving perfect synchronism, that the aural process
thus employed is as nearly fool-proof as any system could be. The
Disney Studios were probably the first to synchronize cartoons by
projecting a wavy line to be used as a tempo guide, or the use of the
bouncing ball. These two methods were abandoned, after a brief
trial, in favor of the present method. For scoring the cartoons, there
are employed an orchestra ranging from twelve to twenty musicians
and four, and sometimes five, effect men for producing sound effects,
in addition to the vocal artists. To synchronize the orchestra is
relatively easy; the greater problem is to synchronize effects, be-
cause of their unmusical character and irregular occurrence. The
effect man has quite a problem, as he sometimes has on his table
dozens of sound producing devices, which he must pick up and
operate at very definite places in the score. With the aural method
of controlling synchronism, he is constantly aware of the tempo,
and his attention can be concentrated on his musical score and
effects. It is not necessary for him even to follow the lead of the
conductor, except at the start. The actual recording technic is
approximately the same as used to record any orchestra.
To facilitate cutting the sound track, acoustical beats are recorded
at the beginning and at the' end of the take. These beats are con-
trolled by the musical director. A predetermined number of beats
are produced in synchronism with the controlling tempo, followed
by a predetermined time interval in which no sound occurs, pre-
ceding the first bar of the music. This enables the cutter to deter-
mine, with absolute accuracy, the exact start of the sound take.
It is quite possible, and has been the practice of this studio, to as-
semble the sound track from these visible indications on the film,
assemble the picture negative from the exposure sheets, attach
academy trailers, and make a composite print. Errors in the syn-
chronism are due to errors in supervision.
The dialog is handled in a somewhat different manner. In the
case of dialog that does not follow the tempo of the music, prescoring
is necessary: the dialog is recorded before drawings of the subject
are made. The recorded sound track is sent to the Cutting De-
partment, where a careful analysis of the position on the film and of
the various speech components is made; such components being
322 WILLIAM GARITY
translated into terms of frames on an exposure sheet. The exposure
sheet then indicates to the animator the exact position of each and
every syllable in the dialog and the drawings are made to fit the
particular conditions. In the case of musical or rhythmical dialog,
it is possible for the animator to make suitable drawings for the
words to be used, and in this case the dialog is recorded at the time
the orchestral recording is made. This form of dialog is one to
be avoided, as in the finished product the composite result sometimes
lacks realism; whereas in the first method of prescoring, it is quite
possible to make the audience feel that the cartoon character is
actually talking.
A METHOD OF MEASURING AXIAL CHROMATIC ABERRA-
TION IN AN OBJECTIVE LENS*
W. HERRIOTT**
Summary. — A method of measuring axial chromatic aberration is described in
which an image of a line grating test object illuminated by a monochromator is formed
by the lens under test. The image thus formed is projected onto a steeply inclined
photographic plate by means of a highly corrected microscope objective. Individual
exposures are made at selected wavelengths and a curve showing the change of image
position as a function of wavelength for the lens under test is readily derived from
measurement of the developed plate. Data are given showing the order of agreement
attained between computed values of axial chromatic aberration and values obtained
by this method.
No commercially available photographic lens offers perfect defi-
nition over an extended field because of the influence of inherent
aberrations. The aberrations are usually so distributed as to result
in the best possible average definition over the required picture area.
In general, such a lens is of high relative aperture and is intended
for use with an object distance that is many times its focal length.
Commercial considerations have4, in certain cases, led to the develop-
ment of special types of lens systems where the lens designer has been
able to meet requirements imposed by special needs. The process
lens is illustrative of this type. In this case, corrections are effected
at a low relative aperture for a magnification of approximately unity,
and particular care is given to the correction of lateral chromatism as
this aberration would obviously prohibit precise registry of negatives
made through trichromatic filters.
Many physical instruments are now in use in which photographic
methods are employed to record a wide variety of transient phe-
nomena. The modern high-speed oscillograph is representative of
this type of instrument; and such instruments, in general, employ
a lens system as a means of imaging an aperture on the plane oc-
* Published by permission of the Optical Society of America; Mr. Herriott's
paper appears simultaneously in /. Opt. Soc. Amer., 22 (April, 1933), No. 4.
** Bell Telephone Laboratories, New York, N. Y.
323
324 W. HERRIOTT [j. s. M. P. E.
cupied by the light-sensitive material. Such imagery may be effected
under a wide variety of conditions for which certain optical factors
may not receive proper design consideration. Such factors involve
the brightness and energy distribution of the light source, the mag-
nification adopted, and particularly the extent of the angular field
required. Factors relating to photographic materials, such as re-
solving power, spectral sensitivity, contrast, and speed, are of equal
importance. We frequently observe instances where commercially
available lenses have been applied to these uses under conditions
widely different from those for which such lenses were originally
designed.
As suggested above, particular considerations may justify the
design of special lens systems in which improved optical efficiency
may be attained by giving close attention to the influence of the
various factors that determine the performance of the instrument.
In some cases, sharp definition may be required only over a limited
field and under conditions where a lens of low relative aperture can be
employed. In case a photographic material of low speed is used,
it may be necessary to increase the relative aperture to a point where
the definition will be affected.
At the Bell Telephone Laboratories consideration has been given
to the choice of a lens system that is required to work with a low-
speed emulsion under illumination conditions that necessitate the
use of the high relative aperture of //1. 5. It is also necessary that
this lens shall give the best possible definition over a limited angular
field of approximately 3.5 degrees. The object consists of a small
illuminated rectangular aperture, which is imaged at the film plane
at a magnification of approximately 0.5. The particular lens that
was used for this purpose served well until it became desirable to
increase the sharpness of the image. Lens bench examination of the
image structure indicated the presence of axial chromatic aberration.
A photographic method of measuring axial chromatic aberration
has been applied to a study of this and similar lenses. The method
involves the projection of an image formed by the lens under test onto
a steeply inclined photographic plate.
Fig. 1 shows schematically the apparatus used. The slit of a
constant deviation spectrometer is illuminated by a small coil fila-
ment tungsten lamp and condenser. These units are adjusted to
form an out-of -focus image of the closely spaced coil filament at the
slit. The eyepiece of the spectrometer has been removed, and a test
April, 1933]
MEASURING ABERRATION IN A LENS
325
object consisting of five transparent lines 0.001 inch wide and 0.250
inch long, separated by opaque lines of the same dimensions, is
placed at the approximate focus of the telescope objective. Im-
mediately behind this test object is located a small piece of finely
ground glass, which serves to permit filling of the aperture of the
lens under test, which is shown to the right of the test object. The
lens under test forms an image of the test object at a magnification
of 0.5. The total width of the test object is limited to 0.010 inch,
in order that a reasonably pure monochromatic radiation will be
transmitted to the lens. A 16-millimeter Bausch & Lomb apochro-
SLIT
COIL
iFILAMENT
i LAMP
FIG. 1. Schematic diagram of apparatus for measuring axial chromatic
aberration.
matic microscope objective serves to relay the image of the test
object formed by the lens under test to a steeply inclined photographic
plate at a magnification of 10.0. The image formed by the micro-
scope lens lies, of course, in a plane perpendicular to the optical axis,
and the inclined photographic plate records a trace of the focal
region surrounding a focal point. The position of the constant
deviation prism in the spectrometer can be altered, and a reading of
the wavelength scale indicates the wavelength of the radiation
incident upon the test object. Assume that a wavelength of 4000 A
is illuminating the test object, the lens under test will form an image
326
W. HERRIOTT
[J. S. M. P. E.
of the test object that will lie at some distance in advance of the
first principal focal point of the microscope objective. The image
formed by the microscope objective will lie at a definite distance
to the rear of its second principal focal point. If an axial movement
of the image of the test object formed by the lens under test occurs,
it is obvious that a shift of the image formed by the microscope
objective will also occur.
A series of exposures is made on a single plate. These exposures
differ only in respect to the wavelength of the light incident upon
the test object. If the color curve is not flat, the images of the test
^100
u
o
a: 75
I
2 25
150
,100
50
1
E
IXPOSl
JRE
TRA
MSMISS
ION
-<x
X
N
\
/
\
A
|6500 6000
5500 5000
4500
A
000
FIG. 2. The transmission characteristics of the dense flint prism used in
spectrometer; also a correcting factor applied to exposures to compensate for
the loss.
object formed by the lens under test will occupy different image
planes. This shift of image plane with wavelength will be indicated
on the inclined photographic plate as a change in position of the
point of sharpest definition. This change in position will, of course,
be a function of the wavelength of light used, and is directly depen-
dent upon the nature of the axial chromatism of the lens under test.
In this manner we can trace a curve connecting the series of points
on the inclined photograph, which will represent on a greatly en-
larged scale the values of axial chromatic aberration of the lens under
test.
April 1933]
MEASURING ABERRATION IN A LENS
327
The dense flint prism used in the spectrometer exercises a high
absorption in the ultra-violet region. Fig. 2 shows the transmission
characteristic of this prism, and also shows a correction factor that
is applied to exposures in order to compensate for this loss.
Fig. 3 has been made in the above described manner, and shows a
600
5OO
4 4OO
FIG. 3. Plate combining series of exposures showing
shift of image plane with wavelength; the dots show
roughly the points of sharpest definition.
change in the point of sharpest definition as a function of wave-
length. The black dots serve only roughly to locate the various
points of sharpest definition.
Fig. 4 shows a comparison between computed values of axial
chromatic aberration and values obtained by three methods of
measurement. A curve is shown that represents a visual examination
328
W. HERRIOTT
[J. S. M. P. E.
of the lens in which a ten-power eyepiece was used with the 16-mm.
apochromat micro-objective in the normal way. A direct-reading
micrometer gauge was attached to the microscope, focal settings
0.3 12
10
^•2*8
1
M
,
a COMPUTED
o FOCUS PLATES
A VISUAL
V FOCAL REGION PLATE
j
$/
A
>*/
I
i
: O.I 4
2
0 0
//
/
A
<^
/S
/
1
*H
^>
^b
t=4—
5C
£^€
'^y
J6500 6000 1 5500^
C D
00 T 4500 14000
F G H
WAVELENGTH IN ANGSTROMS
FIG. 4. Comparison between computed values of axial chromatic aberration
and values obtained by three methods of measurement.
FIG. 5.
A focal region plate made on a process type of emulsion;
exposure constant for all wavelengths.
were made on the image of the test target visually, and the differences
were noted. A curve is also shown, designated "focus plates,"
which resulted from an examination of an extended series of photo-
graphs of the image of the test object obtained with the 16-mm. micro-
April, 1933]
MEASURING ABERRATION IN A LENS
329
scope objective when the photographic plates were placed normal
to the optical axis of the objective. The microscope and plate were
moved longitudinally through an extended range, and many ex-
posures made at definite settings for each selected wavelength.
This process was repeated at all desired wavelengths; a visual
examination of the plates indicated the location of the plane of
sharpest definition, and a curve was readily plotted that shows
these results in graphical form. The fourth curve was derived from
the focal region plate shown in Fig. 3. An average curve would
result in a departure of less than 0.001 inch between the computed
SOO
FIG. 6.
A more favorable condition attained by using a newly
designed lens.
and all the observed values. The particular lens used for these tests
has an equivalent focal length of 1.500 inch.
The photographic emulsion with which this lens is used is sensitive
only to the blue and violet, and Fig. 5 shows a focal region plate
made on a process type of emulsion for which a constant exposure
has been given at all wavelengths. It is obvious that the greatest
photographic effect occurs at 4200, 4400, and 4600 A, with a lesser
effect at the other wavelengths shown. This figure shows clearly
the unfavorable state of axial chromatic correction that exists in this
lens over the portion of the spectrum to which this material is sensi-
tive.
330
W. HERRIOTT
[J. S. M. P. E.
Consideration of these results by the lens designer has led to the
design of a new lens for which a much more favorable condition is
attained, as shown by Fig. 6. Fig. 7 shows this correction plotted on
the same scale used on Fig. 4. The departure from a flat character-
istic is of the order of 0.001 inch at 4000 and 5000 A. At intermediate
values where the radiation is most effective in building up density,
we note that the curve is essentially flat. Fig. 8 represents focal
region exposures for both the above-mentioned lenses, made in a
MILLIMETERS
2 £
MILS
o ro £» o a
11 1
•••»
S
^
^<
/
|6500 6000
5500 5000 [ 4500 | J4000
WAVELENGTH IN ANGSTROMS
FIG. 7. The correction in Fig. 6 plotted on the same scale as in Fig. 4.
FIG. 8. Focal region exposures for the two lenses.
similar manner, excepting that the spectrometer was removed
and the tungsten light source focused directly on the test object.
A difference in the quality of definition offered by these two lenses is
readily shown. Contrast is decidedly improved with the new lens,
and other tests have indicated a very definite improvement in sharp-
ness of the image. Fig. 9 shows values of axial chromatic aberration
for the 16-mm. apochromat microscope objective as determined
visually at Bell Telephone Laboratories, and also shows the corre-
April, 1933]
MEASURING ABERRATION IN A LENS
331
spending values derived by computation. The author wishes to
acknowledge the courtesy of the Bausch & Lomb Optical Company
in making these data available. These values were obtained in
order to determine the possible influence of the characteristics of the
microscope objective on the results obtained with the focal region
plate method.
It is obvious that the apochromatic type of objective offers a very
flat color characteristic over an extended wavelength range. Such
lenses can be manufactured in the smaller sizes with a high relative
aperture, and can be corrected for the desired magnification. The
increasing use of this type of objective might be expected where
0.2
2 O.I
_T
16 MM APOCHROMAT
COMPUTED
VISUAL OBSERVED
=-=
:.
=r^^
---
• :
"
^=^=r-:
==t=
-•»-•— ^—
—
— T
^
6500
60001 5500 5000 I
D F
WAVELENGTH IN ANGSTROMS
| 4000
H
FIG. 9. Axial chromatic aberration for the 16-mm. apochromat microscope
objective; also corresponding values derived by computation.
critical definition is required over a narrow field. The limit in the
size, focal length, and aperture that can be obtained with the apo-
chromat construction appears to be established by the availability
of suitable material for its construction.
Consideration is being given to the possible application of the
above-described method of test to the measurement of spherical
aberration in lenses. The use of a single rectangular aperture at the
test object, together with a series of apertures immediately in front
of the lens under test, may serve to make possible the accurate
determination of crossing distances for the various zones of the
lens.
A NEW WAY OF SPLITTING SECONDS*
C. H. FETTER**
Summary. — In timing races by the usual method employing a manually operated
stop-watch, errors are liable to arise independently of the accuracy of the timepiece.
In order to eliminate this cause of error, a system of timing races has been devised
employing a motion picture camera, with which are photographed a very accurately
adjusted chronometer at both the beginning and the end of the race, and the contestants
themselves at the finish line. This system has been applied successfully at recent
important athletic meets held in the U. S.; particularly at the Xth Olympiad held
at Los Angeles in 1932.
From the earliest recorded history of man we have seen evidence
of human interest in all sorts of athletic sports. Track and field
events were popular in the days of ancient Greece and our present
Olympic Games originated there centuries ago. Not only has man
always been interested in the purely competitive angle of racing
events, but in recent years he has become more and more interested
in the performance of the individual with respect to time, in addition
to his performance against a suitable competitor. On this basis na-
tional and world records have been established in order to classify
the performance of the individual in terms of an invariable quantity
such as time, where a contestant may compare his own performance
either with that of some one who preceded his athletic activities,
possibly by years, or with other contestants in different localities.
In dealing with this so-called invariable quantity, time, the ordinary
method employed of timing a race has been by means of a stop-
watch. Until several years ago stop-watches giving time to a pre-
cision of one-fifth second were used, but more recently tenth-second
stop-watches have been universally employed. In track work, for
example, the competitors are started by the firing of a gun. The
timers are usually located near the finish line of the race in order to
time the finish properly. The timer operates a stop-watch at the
flash of the gun when the race is started, and operates it again as the
* Reprinted from the Bell Telephone Quarterly, XI (Oct., 1932), No. 4, p. 293 .
** Electrical Research Products, Inc., New York, N. Y.
332
NEW WAY OF SPLITTING SECONDS 333
runner crosses the finish line. This procedure inherently contains
the possibility of three errors: (1) it is practically impossible for a
human being to operate a stop-watch coincident with the firing of the
gun because of the human reaction-time involved; (2) it is ex-
tremely difficult for a timer to operate his stop-watch at the finish of
the race coincident with the man's crossing the line, and while this
error is probably less than the starting error because the timer has an
opportunity to anticipate the finish, it is still very much in evidence ;
(3) the watch itself by virtue of being built for a precision of a tenth
of a second would register the nearest tenth when the timer has
operated it. In addition, there is likely to be an accumulative error
in a stop-watch depending upon its adjusted rate as a timepiece.
In addition to the question of time performance, judging a race is
by no means a simple problem. In a close finish it may be very
difficult to decide not only who is first, but also the order of finish of,
for example, the first five. A runner may be blanketed by a competi-
tor so that the judge is confused as to which runner he is called upon to
judge. As a matter of fact, in an important meet not long ago a man
who ran second was not placed at all because of the human error in
observation.
This state of affairs in regard to track events has been known
to exist for some years. Four or five years ago Mr. Gustavus T.
Kirby, Chairman of the Advisory Committee of the Intercollegiate
Association of Amateur Athletes of America (I. C. A. A. A. A.), who
has been interested in amateur sport activities for many years, con-
ceived the idea of photographing the finish of a race in order to de-
termine the proper position of the contestants. He included in this the
idea of somehow photographing the time of the contestants as well,
and in 1931 he used a motion picture camera that photographed both
the finish of the race and the face of an ordinary stop-watch. The
scheme that he used was that of starting the stop-watch before the
race was started, and recording on the motion picture film a flash of
light operated by a contact in the starter's gun. By subtracting the
readings on the photograph of the stop-watch at the beginning from
those of the finish of a race the time could be determined to the
nearest tenth of a second.
In the summer of 1931, several individuals at Electrical Research
Products, Inc., were discussing the possibilities of applying to the
problem in some way Bell System technical knowledge of precision
timing work. This was done in complete ignorance of any progress
334 C. H. FETTER [j. s. M. p. E.
that had been made along this line and, strangely enough, the same
conclusion was reached that was found by Mr. Kirby and his asso-
ciates; namely, that the only satisfactory method by which a race
could be timed and judged was to use a high-speed motion picture
camera arranged to photograph both the performance and the time.
Obviously, this process would provide a permanent record of each
event, which would be of value.
Through a fortunate occurrence in endeavoring to investigate
the situation those engaged in the work met Mr. Kirby and discussed
the problem with him. They were extremely interested to learn of
his activity along this line, and felt that the company could make a
very important contribution to the improvement of timing apparatus,
in that it could build a frequency standard that would permit timing
if necessary to one one-hundredth or even to one one -thousandth of a
second. The need of such precision in timing a foot-race becomes
evident when it is realized that in the faster races, including races as
long as a half mile or a mile, a man may run a yard at the finish in a
tenth of a second. After discussing this matter with Mr. Kirby, work
was begun to develop suitable apparatus for experimental use at the
I. C. A. A. A. A. and the Olympic Games in 1932, for which per-
mission had already been granted.
Before design of the apparatus was begun, at least on a model
basis, several preliminary requirements as to its operation were
established: (1) it was decided that for this use a precision of 0.01
second would be satisfactory, as such timing is accurate to within
three or four inches in the position of the runner; (2) use of the
photographic method appeared absolutely essential; (3) it was
considered desirable to devise a means of photographing the reading
of the clock at the finish of the race to show the actual time of the
runner. This meant that the clock must be reset to zero before
the start of the race and be started practically instantaneously with
the firing of the gun. The Bell Telephone Laboratories were asked to
design a tuning-fork generator and a motor-driven clock mechanism
that would meet these requirements.
In the development of this system it was decided to make two
clocks, one associated with the camera, with which the time and the
finish of the runner could be photographed adjacently on the same
film; and another, that could be started in the same manner as the
first so arranged as to be hand-stopped, so that one of the timers
could use this precision clock as a sort of "glorified" stop-watch, by
April, 1933]
NEW WAY OF SPLITTING SECONDS
335
means of which the time, except for human error at the finish, could
be read to the hundredth of a second immediately following the race.
The system that was developed consists primarily of a 200-cycle
tuning-fork generator which drives a synchronous motor at a speed
of ten revolutions per second. The motor shaft is connected to a clock
mechanism by means of a magnetic clutch so arranged that the clock
FIG. 1. The 200-cycle generator.
dials, which are normally reset to zero and are stationary, are set in
motion when the starter's pistol is fired.
In designing the clock-work itself, some consideration was given to
the type of record to be obtained. First of all, it was decided to use
a standard 16-mm. camera, which takes 128 pictures per second.
Inasmuch as most of the picture area in the 16-mm. film must be
devoted to the action of the contestants, it was decided to use three
336
C. H. FETTER
[J. S. M. P. E.
rotating dials and a fixed hair-line in order to obtain the time on the
film in the largest possible characters. By the use of rotating dials
it was necessary to photograph only a small segment of the entire
dial arrangement. Three concentric dials were used. The inner
dial rotates at one revolution per second and has one hundred di-
visions on it. The middle dial rotates at one revolution per minute
with sixty divisions, and the outer dial rotates at one revolution
FIG. 2. Assembly of the camera, clock, and control box.
per hour with sixty divisions. Thus minutes, seconds, and one-
hundredth seconds can be conveniently read.
Fig. 1 shows a photograph of the 200-cycle generator used in this
model and Fig. 2 shows an assembly view of the camera, the clock,
and a control box designed to provide the necessary power. The
whole system is operated from alternating current of 110 volts.
April, 1933]
NEW WAY OF SPLITTING SECONDS
337
338 C. H. FETTER [j. s. M. P. E.
The optical system provided to photograph the clock dials can be
seen at the left rear end of the main camera lens assembly.
This system was first tried out at the Columbia-Syracuse track
meet at Baker Field, New York, on May 14, 1932. Fig. 3 shows the
first race to have been timed with this system. It was the 100-yard
dash, in which the time as shown to the nearest hundredth of a second
was 10.26 seconds. At the Princeton-Cornell meet at Princeton on
May 21, 1932, the system was successfully demonstrated, and on
June 19, 1932, the apparatus was sent on the Intercollegiate special
train which ran from New York to Berkeley, California, for demon-
stration at the I. C. A. A. A. A. meet there on July 1 and 2.
An example of the results obtained at Berkeley is illustrated in
Fig. 4, which shows Carr of Pennsylvania winning the 440-yard dash
in 46.99 seconds. Even though the camera operates at such high
speed, all the final events on Saturday, July 2, were recorded on less
than 60 feet of film, because the camera is operated only as the runners
cross the finish line.
At Palo Alto on July 15 and 16, the American Olympic try outs
were held, and photographs were obtained of the finish of every
"heat" and "final" at those tryouts. As an example of how difficult
it is to judge a race, Fig. 5 shows the finish of the 100-meter final at
these tryouts. Metcalf finished first in a time of 10.62 seconds, but
there were at least four runners who were not more than a yard or so
behind him. Such a grouping of runners shows how difficult it is to
judge a close race by the eye alone. Note that the camera position
is above the finish line as well as in line with it so that it becomes less
difficult to judge the finish properly. At Palo Alto on July 16, the
film was shown to the American Olympic Committee, and great
interest in the timing system used was expressed. As a matter of
fact, the committee confirmed one of its own decisions through the
showing of the pictures, and reversed the fourth and fifth positions
in one event because of the camera evidence.
From July 31 to August 7, inclusive, this apparatus was in use
at the Xth Olympiad held at the Olympic Stadium in Los Angeles,
California. A few days prior to the opening of the games some of
the pictures taken at Palo Alto were shown to the Olympic Com-
mittee, and based upon that evidence the following status was given
the timing system: (1) it would be used officially for judging; (2)
the hand-stopped clock associated with the system would be used as
April, 1933 ] NEW WAY OF SPLITTING SECONDS 339
one of the timers, of which there were five; (3) it would be used
officially for timing the decathlon.
The camera clock was located 60 feet back from the finish line and
on top of a 25-foot steel tower, as shown in Fig. 6. Throughout the
Olympics every trial, semi-final, and final was timed. Fig. 7 shows
Tolan breaking the world's record in the 200-meter run with a
camera-recorded time of 21.12 seconds. His official time for this race
was 21.2 seconds. Fig. 8 is interesting because it shows one of the
official photographs taken from the top of the judges' stand for this
same race. In the lower left-hand corner can be seen the hand-
stopped clock; and the timer, who is operating it, is kneeling in the
immediate foreground. Fig. 9 shows Lord Burleigh of England in
fifth place of the 110-meter hurdles. This illustrates how the time
of each contestant can be determined, as well as that of the winner.
This picture is also particularly interesting because it was in this race
that Finlay of Great Britain was awarded third place, reversing the
decision of the judges, who had awarded it to Keller of the United
States before the pictures were seen. The foot of the winner is just
visible at the left side of the picture and Finlay is running in lane 3.
Keller of the United States is running in lane 7, the farthest one from
the camera. Two other decisions of a minor nature were reversed
by the judges after seeing the pictures.
As an example of how the official times compared with the recorded
photographed time, figures are given below for some of the Olympic
finals :
Difference — Official
Official Camera Time Used as
Race Time Time Reference
100-Meter Run 10.3 10.38 +.08
110-Meter Hurdle 14.6 14.57 -.03
200-Meter Run 21.2 21.12 -.08
400-Meter Run 46.2 46.28 +.08
400-Meter Hurdle 51.8 51.67 -.13
800-Meter Run 1:49.8 1:49.70 -.10
At a meeting of the International Amateur Athletic Federation
after the games were over, this body in an official report praised the
use of the timing system and recommended that hundredth-second
timing be adopted as a world standard. It also officially invited us
to time the Olympic Games to be held in Berlin in 1936.
While at the Olympic Games in California, Mrs. Amelia Earhart
340
C. H. FETTER
[J. S. M. P. E.
FIG. 7. The finish of the
200-meter race at the Xth
Olympiad.
Xth Olympiad Committee, Official Photograph
FIG. 8. An official photograph taken from the judges' stand
April, 1933]
NEW WAY OF SPLITTING SECONDS
341
Putnam, having seen and heard of this method of timing, stated
that it should certainly be used for airplane races. As a result of this
statement, the National Aeronautic Association was approached;
and through the courtesy of Dr. Lewis and other members of the
Contest Committee, the apparatus was used in collaboration with the
RACE 2
<- Start 30: 1410
Finish 30: 37.30-*
Time 23.20 sec.
Speed 289.32 MPH
RACE 3
Start 33: 25.78 -»
^-Finish 33: 48.09
Time 22.31 sec.
Speed 300.86 MPH
RACE 4
«- Start 35: 42.10
Finish 36: 05.35-*
Time 23,25 sec. j
Speed 288.70 MPH
RACES
Start 39: 58.42-*
4-Finish 40: 20.74
Time 22.32 sec.
Speed 300. 73 MPH J
FIG. 10. Cleveland air races. 3-kilometer speed record. Major James
Doolittle. Average speed (four consecutive trials) 294.90 mi. per hr.
official timing means at the Cleveland Air Races, August 28 to Sep-
tember 5, inclusive. In order to time a straightaway airplane speed
trial, it was necessary of course to have two camera clocks operating
in synchronism from one generator, one to photograph the be-
342 C. H. FETTER
ginning, a second to photograph the finish of the race. The second
camera was obtained and modified, and two camera-operated clocks
were used at Cleveland. All the straight-away races in which there
was any indication that a speed record might be broken were photo-
graphed.
Fig. 10 shows Major Doolittle breaking the world's record for land
planes over a 3-kilometer course. These pictures are not, of course,
official; but it is interesting to note that the official average speed
made by Major Doolittle as determined by the official method was
294.48 miles per hour, while the speed determined by the camera
clock was 294.90 miles per hour.
A METHOD FOR THE CALCULATION OF THE CORRECT
AND MOST ECONOMICAL CONCENTRATIONS OF
ELON AND HYDROQUINONE IN A BORAX
DEVELOPER FOR MOTION
PICTURE FILM*
ALAN M. GUNDELFINGER**
Summary. — Holding temperature, developing time, and agitation constant, the
following relations exist: (1) In an elon-borax-sulfite developer, sulfite held constant
and borax varied with the elon, j = K log E -\- C, where E = elon cone, and K and
C = constants: (2) In an elon-hydroquinone-borax-sulfite developer, hydroquinone
and sulfite held constant and borax varied with the elon, 7 = K log E + C, where
E = elon cone, and K and C = constants: (3) In an elon-hydroquinone-borax-
sulfite developer, elon, borax, and sulfite held constant, 7 = K log H + C, where
H = hydroquinone cone, and K and C = constants: (4) In an elon-hydroquinone-
borax-sulfite developer, sulfite held constant and borax varied with the elon, 7 =
Ki log E + Kz(log E)(log H) + K3 log H + KI, where E = elon cone., H
= hydroquinone cone., and K\, K^, K%, K± = constants: (5) In an elon-hydro-
quinone-borax-sulfite developer, 7 and sulfite held constant, and borax varied with
the elon, there exist optimum concentrations of elon and hydroquinone for maximum
economy.
Carlton and Crab tree1 have stated, "If borax is added to convert
the elon into the elon base, the rate of development increases with
the elon concentration. The gamma produced for a constant time
of development increases as a linear function of the logarithm of the
elon concentration."
The purposes of this investigation were as follows :
(1) To verify the statement of Carlton and Crabtree concerning the exponential
relation between elon and gamma in an elon-borax-sulfite developer.
(2) To determine whether or not the same, or any other relation, exists between
elon and gamma in an elon-hydroquinone-borax-sulfite developer (hydroquinone
maintained constant).
(3) To determine the relation between hydroquinone and gamma, if any, in an
elon-hydroquinone-borax-sulfite developer (elon maintained constant).
* Reprinted from /. Franklin Inst., 214 (Aug., 1932), No. 2, p. 223.
** Chemical engineer, Hollywood, Calif.
343
344 ALAN M. GUNDELFINGER [J. S. M. P. E-
(4) To determine, if possible, the relation between gamma, elon, and hydro-
quinone in an elon-hydroquinone-borax-sulfite developer (elon and hydroquinone
both variable).
(5) To derive a method for calculation of the most economical concentrations
of elon and hydroquinone, provided that the function of gamma, elon and hydro-
quinone can be evaluated.
I. LABORATORY PROCEDURE
(a) Film Stock. — In performing the series of tests for this investi-
gation it was thought advisable to use negative stock, which reacts
considerably better with borax developers and has greater latitude
than positive stock, and to use one with which a fair amount of light
could be used in the dark room. Consequently, Eastman ortho-
chromatic No. 1201-171 was chosen.
(b) Sensitometric Exposures. — Sensitometric strips were exposed
on an Eastman Type lib sensitometer with a lamp and filter ac-
curately calibrated, by the Eastman Kodak Co., as to intensity and
color temperature (5400 °K.) and a time scale in powers of \/2.
(c) Development. — Development of the Sensitometric strips was
performed in the following manner :
Two strips were fastened, emulsion side up and adjacent to each
other, to a piece of plate glass. The plate of glass was dropped,
simultaneously with the releasing of a timing device, into a tray
containing just sufficient developer to cover the strips. The tem-
perature of the developer was maintained at 18° =•= 1°C. Immedi-
ately after dropping the plate of glass into the developer, brushing
of the strips was started. A camel's-hair brush, wide enough to
cover both strips, was used, and the brushing was accomplished with
a uniform reciprocating stroke of length equal to that of the strips.
The rate of brushing was maintained as constant as was humanly
possible. At the instant of the sounding of the time signal, indicat-
ing completion of the required development time, the glass plate with
its attached strips was transferred bodily to an adjacent tray con-
taining hypo solution, after which the strips were thoroughly washed
and dried. The time of development in all cases was maintained at
5.0 minutes, and the time of hypo immersion was considerably more
than sufficient for the complete removal of all undeveloped silver
halide.
(d) Density Determination. — Densities on the developed Sensi-
tometric strips were determined with a Western Electric densitom-
eter using a Bausch & Lomb head of the polarizing type. The
April, 1933]
BORAX DEVELOPER FOR FILM
345
observations were made with the emulsion side of the strips down-
ward, against the diffusion glass.
(e) Curve Plotting. — In plotting the H & D curves, the average
density of corresponding exposures, on two strips developed simul-
taneously, was plotted against the logio of the absolute exposure.
(/) Developers. — All developers used in this investigation contained
300.0 gm. of sodium sulfite per gallon, and a quantity of borax,
per gallon, equal to the weight of elon, in grams per gallon, plus
8.0. In explanation, it might be well to call attention to the fact
that since elon requires approximately an equal quantity, by weight,
of borax in order to be converted into the elon base,1 this arrange-
ment was utilized so that a theoretical excess of 8.0 gm. of free borax
20
1.8
/6
'0
* 0.8
0.6
0.4
0.2
Curve Mo
O3/
234
O.44 O.S7 O69
SO SO SO SO
2O 4.O 8O /6O
/O O /2.O /6-O 24 O
fya/J 3OO.O 3OOO JOO-O 3OO.O
-2.A5
-/.S3 -O.93 -O-35 0.27 0-&7
FIG. 1. H & D curves of elon-borax-sulfite developers.
would always be available to accommodate the slightly low pH
value of hydroquinone without seriously affecting the pH value of the
developer.
The four fundamental developers used were as follows :
Elon (gm./gal.)..
Borax (gm./gal.)
Sulfite (gm./gal.)
In addition, sixteen more developers were used consisting of each
of the above-tabulated developers containing, in addition, 2.0, 4.0,
8.0, and 16.0 gm., respectively, of hydroquinone per gallon.
developers
1
2 0
2
4.0
3
8.0
4
16.0
10 0
12.0
16.0
24.0
)..
300.0
300.0
300.0
300.0
346
ALAN M. GUNDELFINGER
[J. S. M. P. E.
II. RELATION BETWEEN GAMMA AND ELON IN AN ELON-BORAX-SULFITE
DEVELOPER
Fig. 1 shows the H & D curves obtained from the four fundamental
developers without hydroquinone. Fig. 2 shows the curve obtained
/.o
O.9
08
07
0.6
05
0.4-
03
0.2
O./
01
FIG. 2.
2.0
J.8
0.8
O.<5
0.4
0.2
FIG. 3.
Borax Cone --/# Ogm +gm. E/dn)/oa/
5 u/ fife Cone -- 300.0gm./ya/
Where Kand C= Constants
andE*E/on Cone.
E/on Cone (gm/ya/J
0.2 030.405 1.0 2.0 304050 1 0.0 20.030.0
Gamma vs. elon concentration; for elon-borax-sulfite
developers.
Curve A/o. /
Ga/ns77a. O.33
fiey. 7/S770 //V//7/ *5~-O
fc/TT./fO/J 2.O
2.O
/O-O
0.47 O.S<3 0.67
S.O S-O &O
4.O SO /6.0
2.0 2.0 2.0
/2.0 /6-O 24-0
3OO.O3OO.O 3OO.O 3OO-O
0.87
H & D curves for elpn-hydroquinone-borax-sulfite de-
velopers (hydroquinone, 2 gms./gal.).
by plotting gamma against log elon concentration. Examination of
the curve reveals the fact that the general equation is:
T = #log£ + C (1)
where K and C = constants and E = elon concentration.
April, 1933]
BORAX DEVELOPER FOR FILM
347
Evaluating the constants of the equation for the curve best repre-
senting the data, the following equation is obtained:
7 = 0.4321ogi0E + 0.18
If, now, in equation (1), 7 is differentiated with respect to E, then,
dy
dE
(2}
or the derivative or slope of the 7-elon curve is inversely proportional
to the elon concentration and the proportionality constant is the
slope of the 7-log R curve. In other words, the rate of change of 7
with respect to elon concentration, holding temperature, agitation,
and development time constant, is inversely proportional to the
elon concentration.
2.0
/6
/6
/.4
-
/.O
0.8
O.6
O.4
0.2
Cunse/Vo.
/ 2 3 4
O-42 O-S/ O-6O O.67
MyarDfutnone ••
Sorax
Su/f/te " 3OO-O
0.37
FIG. 4. Same as Fig. 3 (hydroquinone 4 gms./gal.).
III.
RELATION BETWEEN GAMMA AND ELON IN AN ELON-HYDROQUINONE-
BORAX-SULFITE DEVELOPER
Figs. 3, 4, 5, and 6 show the H & D curves obtained from the four
fundamental developers containing 2.0, 4.0, 8.0, and 16.0 gm. hydro-
quinone, respectively. Fig. 7 shows the curves obtained by plotting
gamma against log E in the presence of constant concentrations of
hydroquinone. It can be observed quite readily that the same
general relation exists between 7 and elon concentration, in the
presence of a fixed concentration of hydroquinone, as exists in the
absence of the latter. That relation may be represented also by
equations identical to (7) and (2).
348
ALAN M. GUNDELFINGER
[J. S. M. P. E.
IV. RELATION BETWEEN GAMMA AND HYDROQUINONE IN AN ELON-
HYDROQUINONE-BORAX-SULFITE DEVELOPER
Inasmuch as the reaction of hydroquinone, as well as other de-
veloping agents, on the silver halide grain is primarily one of reduc-
*
i
2.0
/.Q
/.o
O.8
O.6
0.4
0.2
Curve Afo-
Go/n/na.
Dev. T/snefM/r?)
£/of?
0.
OSS 0.64 0.7/
4.O 8.0 /6-O
8O 30 Q.O Q.O
/O-O /2.O /6O 24O
3OO.O 3OO-O 300.O 30O-O
• a i
-0.93 -0.33 0.27 O.&7
FIG. 5. Same as Fig. 3 (hydroquinone 8 gms./gal.).
2.0
/Q
/.O
0.8
0.6
04
0.2
O.68
S-O
2.O 4.O G.O /6O
•• /6-O /6-O /6.O /6.O
•• /O-O /2.O /6-O 24 O
" 30O.O 300.O 3OO-O 300.O
-2. S3
-0.93 -O.33 0.27 O.Q7
FIG. 6. Same as Fig. 3 (hydroquinone 16 gms./gal.).
tion, the mechanics of which should in all cases be similar if not ex-
actly the same, it should be expected that the relation between
gamma and hydroquinone is the same as that between the former
and elon.
April, 1933]
BORAX DEVELOPER FOR FILM
349
Fig. 8 shows the curves obtained by plotting gamma against log
hydroquinone concentration, in the presence of constant concentra-
tions of elon. The data for these curves were obtained, likewise,
from those of Figs. 3, 4, 5, and 6. As was to be expected, it can be
Where Kand C = Constants
and E - Elon Cone
02 03 0405
1.0 20 504050 IOO 200500
FIG. 7. Curves of gamma vs. log elon, for various constant con-
centrations of hydroquinone; data obtained from Figs. 3 to 6, incl.
/.O
O.9
0.8
0.7
0.6
O.5
0.4
0.3
0.2
O./
Curve
/. 23. 4.
O.O67 OO53 O.O45 OO29
2.O 40 8.0 /6.0
y=KLog H + C
Where Kand 'C= Constants
an</H
ftyefroqumone Cone (gm/ga/.)
ai
0.2 03 0.405
1.0
2.0 5.04.05.0
10.0 20.0 300
FIG. 8. Curves of gamma vs. log hydroquinone concentration for
various constant concentrations of elon; data obtained from Figs.
3 to 6, incl.
observed quite readily that the same general relation exists between
gamma and hydroquinone, in the presence of a constant concentra-
tion of elon, as exists between gamma and elon, in the presence of a
350
ALAN M. GUNDELFINGER
[J. S. M. P. E.
fixed concentration of hydroquinone. This relation may be repre-
sented by:
7 = K log H + C (5)
dH = H (4)
where K and C = constants and H = hydroquinone concentration.
V. RELATION BETWEEN GAMMA, ELON, AND HYDROQUINONE IN AN ELON-
HYDROQUINONE-BORAX-SULFITE DEVELOPER
In parts III and IV it has been shown that, holding temperature,
as
0.4
0.3
02
o./
Where C, and C2 - Constants
and H
ttydroyuinone Cone (f
O.I 0.2 0.3 04 OS I.O 2.0 3.0 4.0 SO 100 20030.0
FIG. 9. Variation of the constant K with hydroquinone concen-
tration; elon-hydroquinone-borax-sulfite developers.
agitation, development time, and the concentration of the remaining
constituents constant,
7 = F(E) and 7 = /(#)
and F(E) and f(H} have been evaluated.
Then, if
7 = F(E,H]
it becomes highly desirable to evaluate F(E,H).
Examination of Fig. 7 reveals the fact that K of equations (1)
and (2) varies with the hydroquinone concentration such that
K =
(5)
and equation (2) becomes a partial differential equation, as
57
April, 1933]
BORAX DEVELOPER FOR FILM
351
Likewise, it may be observed from Fig. 8 that K of equations (3)
and (4) is a function of E, or
K =
such that equation (4) becomes a partial differential equation, as
H
If, then, X of equations (1) and (2) is plotted against log H, as
shown in Fig. 9, it is found that there is a linear relation between K
and log H, and $(H) can be evaluated. Then :
K = t(H) = C, - C2 log H (7)
o/
Where Cy and C+ - Consfanfs
and £ = E/on Cone.
O.I
0.2 0.5040.5 1.0 2.0 3.04.05.0 10.0 20.050.0
FIG. 10. Variation of the constant K with elon concentration;
elon-hydroquinone-borax-sulfite developers.
Similarly, K of equations (3) and (4) is shown, in Fig. 10, to bear
a linear relation to log E such that
K = 0(E) = Cz - C* log E (8)
where C\, Cz, €3, and C4 are constants.
Combining equations (5) with (7) and (6) with (£), there results
. Ci - C2 log H
and
Integrating
H
- C4 log E
H
(9}
(10}
352 ALAN M. GUNDELFINGER [j. s. M. P. E.
7 = (C, - C2 log H) log E + /(#) (11)
Differentiating 7 with respect to H in (11),
d7 = a log £ , #
d# H ^ dH
Combining equations (10) and (12),
_d£ = C3 - C< log E C2 log £ C3 + Cs log E
dH H H H
which on integration gives
f(H) = (C3 + C5 log E) log H + Ct
= C3 log H + C5(log E) (log H) + C6
where C& = constant of integration. And on combining equations
(11) and (14) there results
7 = CilogE + Cr(log E) (log H) + C3logH + C6 (75)
or
7 = Ki logic £ + ^2(logio E) (log,0 ff) + ^3 log,0 H + ^4 (^)
Equation (75) becomes, then, the general equation for
7 = /(£, H)
and evaluating the constants from the experimental data, the equa-
tion for the set of conditions in this series of tests becomes
7 = 0.4021og10£ - 0.114(log10E)(log10#)
+ 0.217 logic H + 0.174
where £ = elon concentration in gm. per gallon and H = hydro-
quinone concentration in gm. per gallon.
VI. A METHOD FOR THE CALCULATION OF THE MOST ECONOMICAL
CONCENTRATIONS OF ELON AND HYDROQUINONE IN AN
ELON-HYDROQUINONE-BORAX-SULFITE DEVELOPER
An analysis of equation (15) of part V reveals the fact that an
infinite number of combinations of elon and hydroquinone will satisfy
the equation for any definite gamma. The question then arises as
to the optimum concentration for the two developing agents. The
natural answer to that question is that combination of concentra-
tions which will formulate the least expensive developer.
At present there is a marked difference in the prices of elon and
hydroquinone, that of the former amounting to slightly over three
times that of the latter. The natural impulse would lead to the con-
clusion, then, that the least expensive developer would include
the least possible amount of elon.
April, 1933]
BORAX DEVELOPER FOR FILM
353
Such, however, is not the case, for a glance at the slopes of the
curves of Figs. 7 and 8 will reveal the fact that elon is much the
more powerful reducing or developing agent. Consequently, while
it is the more expensive of the two agents, a lesser concentration of it
is required to produce a definite degree of development than that of
hydroquinone. On the other hand, it is possible to utilize a concen-
tration of elon which is too high for economy.
In order to illustrate this point, let the assumption be made that
the costs of elon and hydroquinone are $3.30 per pound and $1.00
per pound, respectively, and that the desired gamma is 0.5. Then
6.0
7.0
6.0
-
/.o
/.O 2 0
4.O 5.O 6.O 7.O
Cone,
9.O /OO
FIG. 11. Curves showing relation between total cost of developing
agents and concentration of elon, for constant gamma.
by virtue of this assumption and equation (17), a curve (Fig. 11)
has been constructed showing the relation between the total cost of
developing agents per unit volume of developer and the concentration
of elon.
It is apparent that the curve has a marked minimum point and
that there are distinct optimum concentrations of both developing
agents for maximum economy. It is perfectly possible to determine
the minimum point of this curve analytically by making use of the
calculus, but for all practical purposes the increased accuracy is of
354 ALAN M. GUNDELFINGER
no value and does not warrant the procedure, which is quite laborious.
From the curve, it is seen that an elon concentration of 3.3 grn.
per gallon corresponds to the least cost of a developer which complies
with the previously mentioned assumptions and is to be utilized
under the precise experimental conditions of this investigation. The
corresponding hydroquinone concentration is found from equation
(17) to be 5.5 gm. per gallon.
REFERENCE
1 CARLTON, H. C., AND CRABTREE, J. I.: "Some Properties of Fine Grain
Developers for Motion Picture Film," Trans. Soc. Mot. Pici. Eng., XIII (1929),
No. 38, p. 406.
SOCIETY OF MOTION PICTURE
ENGINEERS
OFFICERS
1933
President
A. N. GOLDSMITH, 570 Lexington Ave., New York, N. Y.
Past-President
J. I. CRABTREE, Eastman Kodak Company, Rochester. N. Y.
Vice-Presidents
E. I. SPONABLE, Fox Film Corp., New York. N. Y.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
Secretary
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
Treasurer
H. T. COWLING, Rochester, N. Y.
Board of Governors
H. T. COWLING, 1430 Monroe Ave., Rochester, N. Y.
J. I. CRABTREE, Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
P. H. EVANS, Warner Bros. Pictures, Inc., 1277 E. 14th St., Brooklyn, N. Y.
R. E. FARNHAM, General Electric Co., Nela Park, Cleveland, Ohio.
O. M. GLUNT, Bell Telephone Laboratories, Inc., New York, N. Y.
A. N. GOLDSMITH, 570 Lexington Ave., New York, N. Y.
H. GRIFFIN, International Projector Corp., 90 Gold St., New York, N. Y.
W. C. HUBBARD, General Electric Vapor Lamp Co., Hoboken, N. J.
R. F. MITCHELL, Bell & Howell Co., 1801 Larchmont Ave., Chicago, 111.
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
E. HUSE, Eastman Kodak Co., 6706 Santa Monica Ave., Hollywood, Calif.
E. I. SPONABLE. Fox Film Corp.. 850 Tenth Ave.. New York. N. Y.
355
SOCIETY ANNOUNCEMENTS
SPRING, 1933, CONVENTION
HOTEL PENNSYLVANIA, NEW YORK, N. Y
APRIL 24 TO 28, INCLUSIVE
Arrangements for the approaching Spring, 1933, Convention, to be held at New
York, April 24 to 28, with headquarters at the Hotel Pennsylvania, are rapidly
proceeding, the plans including a number of outstanding presentations that will
make it worth every one's while to be present at the meeting. Standardization
is to play an important part in the proceedings. The economy trends in sound
picture production and exhibition that the industry is now showing will be dis-
cussed.
The semi-annual banquet of the Society is to be held on April 26, at the Hotel
Pennsylvania. An evening of pleasure and interest is promised, and all are urged
to make every effort to attend.
Mr. W. C. Kunzmann, chairman of the Convention Committee, is being ably
assisted in his efforts to make the Convention an outstanding success by the
Local Arrangements Committee under the chairmanship of Mr. H. Griffin.
All technical sessions will be held in the Salle Moderne, on the roof of the Hotel
Pennsylvania. Registration will be opened at 9 A.M., Monday, April 24. The
registration fee will be $3, and the banquet charge $4.50.
Plans are being made to assist out-of-town visitors to the Convention to pass
an interesting time while in New York, and special film programs and trips of
interest will be arranged. Final details of the program, including hotel rates
and other pertinent information, will be mailed to the members of the Society at a
later date. Members and friends of the Society are urged to make every effort to
attend the Convention.
EXHIBIT OF NEW MOTION PICTURE APPARATUS
SPRING, 1933, CONVENTION
Arrangements are being made to hold an exhibit of newly developed motion
picture apparatus, in order to acquaint the members of the Society with the newly
devised tools of the industry. This exhibit will not be of the same nature as the
usual trade exhibit. There will be no booths, although each exhibit will be al-
lotted definite space, and all exhibits will be arranged in one large room. The
following regulations will apply:
1. The apparatus to be exhibited should be new or have been developed or
improved within the past 12 months.
2. Each exhibitor will be permitted to display a card giving the name of the
manufacturing concern, and each piece of equipment shall be labeled with a
plain label free from the name of the manufacturer.
356
SOCIETY ANNOUNCEMENTS 357
3. A technical expert capable of explaining the features of the apparatus ex-
hibited must be present during the period of the exhibition.
4. A charge for the exhibit will be made in accordance with the space occupied,
as follows: up to 20 sq. ft., $10.00; 20 to 30 sq. ft., $15.00; 30 to 40 sq. ft., $20.00;
40 to 50 sq. ft., $25.00.
Please direct requests for space to the General Office of the Society, 33 West
42nd St., New York, N. Y., stating the number and nature of the items to be
exhibited.
ARRANGEMENTS PROGRAM
SPRING MEETING OF THE SOCIETY, HOTEL PENNSYLVANIA,
NEW YORK, N. Y.
APRIL 24-28, 1933, INCLUSIVE
COMMITTEES IN CHARGE OF ARRANGEMENTS
NEW YORK LOCAL COMMITTEE
H. GRIFFIN, Chairman
O. M. GLUNT W. C. HUBBARD J. H. KURLANDER
5. HARRIS P. H. EVANS H. RUBIN
M. W. PALMER A. S. DICKINSON M. C. BATSEL
J. E. ROBIN J. H. SPRAY T. E. SHEA
CONVENTION REGISTRARS
W. C. KUNZMANN H. T. COWLING
E. R. GEIB S. R. RENWICK
HOSTESS TO CONVENTION
MRS. E. I. SPONABLE
assisted by
MRS. O. M. GLUNT MRS. H. GRIFFIN
MRS. M. C. BATSEL MRS. W. M. PALMER
Miss DOROTHY HUBBARD
ENTERTAINMENT AND AMUSEMENTS
W. C. KUNZMANN H. GRIFFIN
W. C. HUBBARD J. H. KURLANDER
M. W. PALMER H. RUBIN
P. H. EVANS J. H. SPRAY
BANQUET ARRANGEMENTS
W. C. HUBBARD, Chairman
H. GRIFFIN W. C. KUNZMANN O. M. GLUNT
358 SOCIETY ANNOUNCEMENTS [J. S. M. P. E.
SUPERVISORS OF PROJECTION EQUIPMENT, INSTALLATION, AND OPERATION
H. GRIFFIN, Chairman
JAMES FRANK, JR. G. C. EDWARDS
T. E. SHEA R. MIEHLING
Officers and Members of Projectionists Local No. 306, 1.A.T.S.E., New York.
MEMBERSHIP
H. T. COWLING, Chairman
PRESS AND PUBLICITY
W. WHITMORE, Chairman
CONVENTION SESSIONS
All technical sessions and film exhibitions will be held in the Salle
Moderne, Roof Garden, Hotel Pennsylvania, where also will be lo-
cated the registration headquarters. A meeting room will be pro-
vided for the Board of Governors and the technical committees in
the Roof Garden, off the entrance to the Salle Moderne.
LADIES' HEADQUARTERS
A private parlor suite on the 17th floor of the Hotel Pennsylvania,
directly beneath the Convention Headquarters, will be reserved for
the use of the ladies.
BANQUET AND DANCE
The S.M.P.E. Semi-annual Banquet and Dance will be held in
the Grand Ball Room of the Hotel Pennsylvania, Wednesday
evening, April 26, at 7:30 P.M.: an evening of dancing and enter-
tainment— no banquet speeches.
Banquet tickets should be obtained at the registration head-
quarters; tables reserved for 8 or 10 persons.
Excellent accommodations are assured by the Hotel Pennsyl-
vania, and minimum rates are guaranteed. Room reservation
cards should be returned immediately to the Hotel Pennsylvania in
order to assure satisfactory reservations. Those who will motor to
New York will be granted special daily and weekly car storage rates
at the modern fire-proof garage adjoining the hotel.
The hotel management has arranged for golfing privileges for
members at the Lido Country Club, Lido Beach, Long Island; the
Salisbury Country Club, Westbury, Long Island; and the Queens
Valley Golf Club, Inc., Forest Hills, New York.
April, 1933] SOCIETY ANNOUNCEMENTS 359
NEW APPARATUS EXHIBIT
The exhibit will be held in the Roof Garden of the hotel, adjacent
to the registration headquarters. Please communicate with Mr. S.
Harris, Editor-Manager, at the General Office of the Society, 33
West 42nd Street, New York, N. Y., regarding space and exhibit
regulations.
TENTATIVE PROGRAM
MONDAY, APRIL 24
The morning will be devoted to organization of the convention,
registration of members, and meetings of committees. An informal
luncheon for members, guests, and friends will be held in the Roof
Garden of the Hotel Pennsylvania at 12:30 P.M. Several addresses
will be delivered by prominent speakers.
Luncheon tickets should be obtained at the registration desk and
will be collected at the tables. Don't fail to attend.
2:30 P.M. Salle Moderne.
Convention called to order.
Address by President A. N. Goldsmith.
Report of the Secretary, Mr. J. H. Kurlander.
Report of the Treasurer, Mr. H. T. Cowling.
Convention Announcements, Mr. W. C. Kunzmann.
Papers Committee, Mr. O. M. Glunt, Chairman.
Technical papers program.
8:00 P.M. Salle Moderne.
Interesting program of recent talking motion pictures.
(Admission by registration card.)
TUESDAY, APRIL 25
9:30 A.M. Salle Moderne.
Technical papers program.
2:30 P.M. Salle Moderne.
Technical papers program.
8:00 P.M. Bell Telephone Laboratories.
Lecture and demonstration by Dr. H. E. Ives. Tickets
for this session will be supplied by the registrars.
The laboratories are located at 463 West Street, New
York, N. Y.
360 SOCIETY ANNOUNCEMENTS [J. s. M. P. E.
WEDNESDAY, APRIL 26
9:30 A.M. Salle Moderne.
Technical papers program.
1 :00 P.M. This afternoon is left open for recreation.
7:30 P.M. Grand Ball Room, Hotel Pennsylvania.
S.M.P.E. Semi-annual Banquet. Dancing and enter-
tainment. No banquet speeches.
THURSDAY, APRIL 27
9:30 A.M. Salle Moderne.
Technical papers program.
2:30 P.M. Salle Moderne.
Technical papers program.
8:00 P.M. Salle Moderne.
Popular talk and motion picture program. (Admission
by registration card.)
FRIDAY, APRIL 28
9:30 A.M. Salle Moderne.
Technical papers program.
2:30 P.M. Salle Moderne.
Technical papers program.
Open Forum and Convention Adjournment.
Papers Committee Convention Committee
O. M. GLUNT, Chairman W. C. KUNZMANN, Chairman
NEW YORK SECTION
The monthly meeting of the New York Section was held on March 8 in the
auditorium of RCA Photophone, Inc., at New York, N. Y., approximately one
hundred and twenty members and guests attending. Mr. M. C. Batsel, director
of the Photophone and Applications Division of the RCA Victor Co., described
briefly the development and application of the new RCA high-fidelity recording
and reproducing equipment.
Following his address, a number of short and feature pictures were reproduced,
in order to exemplify the improvements achieved by the new system. The Walt
Disney release, Santa Claus in Toyland, a Mickey Mouse short, and a Van Beuren
animated cartoon, recorded with high-fidelity equipment, were reproduced.
Following these short reproductions, an RKO feature picture entitled Our Betters,
starring Constance Bennett, and recorded on the RCA type PR-4 variable width
recorder (described in the March, 1933, issue of the JOURNAL) equipped with a
special high-frequency response galvanometer, was projected and reproduced.
The galvanometers used for recording, devised by Mr. C. Dreher, were designed
to have an approximately linear response at frequencies up to 8000 cycles.
April, 1933] SOCIETY ANNOUNCEMENTS 361
A general discussion of the equipment and the reproduction, from the standpoint
of recording and reproducing sound, followed the demonstration; after which the
recording and reproducing equipment installed in the auditorium were opened to
inspection by the members, and were ably described by members of the RCA
Photophone organization.
Unusual interest was shown by the audience in the new equipment and in the
technical endeavors being made to improve the quality of recording and repro-
ducing; and that this interest was real and that the meeting was quite successful
were attested to by the fact that nearly the entire audience remained until the
adjournment, which occurred unusually late.
D. HYNDMAN, Secretary-Treasurer
PACIFIC COAST SECTION
The second meeting of the season was held in the theater of Paramount Pro-
ductions, Inc., approximately one hundred and twenty-five members and guests
attending. This meeting emphasized further the plans of the present Board of
Managers to depart from the usual style of meeting dealing primarily with motion
pictures as a means of entertainment. Although the importance of the motion
picture is admittedly greatest in the entertainment field, other fields, including
those of advertising, history, education, etc., are developing so rapidly that the
professional motion picture engineer is obliged to take cognizance of their require-
ments and technological needs. That excursions into these fields are deemed
worth while is attested to by the attendance at the meeting and the amount of in-
terest displayed.
Mr. J. Dubray had been appointed chairman of the Program Committee for
this meeting, and had ably arranged for a session devoted to the application of
motion pictures by the medical profession. A business appointment unfortu-
nately preventing Mr. Dubray from attending the meeting, Dr. D. MacKenzie
kindly consented at the request of Section Chairman E. Huse to act as chairman
of the meeting, in which capacity he ably kept up the spirits of those viewing
the pictures who were unaccustomed to witnessing six-inch close-ups of human
interiors.
The program opened with the projection of a two-reel picture of an appendec-
tomy, in 35-mm. Technicolor, followed by another showing the removal of a
breast cancer; both operations having been performed by Dr. M. Kahn, of the
Cedars of Lebanon Hospital. These pictures were of particular interest in that
they had been photographed by a professional cameraman, Mr. H. Green, under
the supervision of a commercial producing company.
There were also projected two reels of a picture dealing with plastic surgery, the
work of Dr. H. L. Updegraf, also of the Cedars of Lebanon Hospital, in 35-mm.
Magnacolor; followed by a 16-mm. film depicting the complete case history of the
reconstruction of a burned face. The skill shown in this work, which involved
fourteen operations over a period of as many months, evoked a genuine response of
admiration from the audience. Dr. Updegraf 's exhibition was accompanied by an
explanatory talk that left little doubt in the minds of the spectators as to the value
of this kind of application of motion pictures.
Two reels of 16-mm. film illustrating the technics of cystectasy and prostatec-
362 SOCIETY ANNOUNCEMENTS [J. S. M. P. E.
tomy, were exhibited by Dr. E. Belt, who accompanied the projection with a de-
scription of the surgery and the methods employed in obtaining the pictures.
Dr. J. C. Irwin screened about 1000 feet of 16-mm. film showing three examples
of Caesarian section. An interesting feature of this showing was the progress that
had been made in the photography of the three successive operations.
Dr. Lozier, of the University of Southern California, closed the exhibit with a
screening of dental films, demonstrating the advantages of superspeed panchro-
matic negative film over the orthochromatic stock used some years ago.
At the invitation of the chairman, the members of the section were addressed
briefly by Mr. W. C. Kunzmann, vice-president of the Society. Mr. Kunzmann
voiced the appreciation of the Board of Governors and the officers of the Society
for the great activity being shown by the Pacific Coast Section.
The large attendance and the great amount of interest shown in the subject of
the meeting were very gratifying, indicating that fields of application of motion
pictures not frequently explored hold for the motion picture engineer many fea-
tures of technical and general interest.
G. RACKETT, Secretary-Treasurer
SUB-COMMITTEE ON SCREEN BRIGHTNESS AND THEATER
ILLUMINATION
Several meetings of representatives of the several projection committees have
recently been held for the purpose of studying the various problems involved in
measuring, and in arriving at recommendations for, the brightness of projection
screens and the illumination of theater auditoriums.
Upon invitation of the S.M.P.E., a committee was established by the Illuminat-
ing Engineering Society, under the chairmanship of Prof. S. R. McCandless of
Yale University, for the purpose of collaborating with the S.M.P.E. group. The
latter was consequently officially organized, under the name given above, as a sub-
committee of the Projection Screens Committee. The personnel of the sub-com-
mittee follows:
S. K. WOLF, Chairman
A. C. HARDY (Chairman, Projection Theory Committee)
W. F. LITTLE (Member, Projection Screens Committee)
H. RUBIN (Chairman, Projection Practice Committee)
H. B. SANTEE (Chairman, Sound Committee)
PROJECTION PRACTICE COMMITTEE
At a meeting held on March 15, at New York, N. Y., a draft of the report to be
presented at the convention in April was read to the Committee by Chairman
Rubin, for discussion and revision. The report describes the special test reels
that have been developed by the Committee, mentioned in previous issues of the
JOURNAL, and a special tool that has been devised for the purpose of aligning the
arc lamp with the optical axis of the projector; and discusses various problems
incident to change-over marks and their location, and positive print density and
studio screen illumination.
April, 1933] SOCIETY ANNOUNCEMENTS 363
SUSTAINING MEMBERS
Bausch & Lomb Optical Co.
Bell Telephone Laboratories
Burnett-Timken Laboratories
Eastman Kodak Co.
Electrical Research Products, Inc.
National Carbon Co.
RCA Victor Co., Inc.
HONOR ROLL
OF THE
SOCIETY OF MOTION PICTURE ENGINEERS
By action of the Board of Governors, October 4, 1931 , this Honor Roll was estab-
lished for the purpose of perpetuating the names of distinguished pioneers who are
now deceased;
LOUIS AlME AUGUSTIN L/E PRINCE
WILLIAM FRIESE-GREENE
THOMAS ALVA EDISON
GEORGE EASTMAN
JEAN ACME LE ROY
CONFIRMED
BY TIME
It may have been fate that prompted
the perfecting of the first Eastman
motion picture film just when
Edison's first projector demanded it.
But it was time's judgment of its
merit that again and again confirmed
Eastman film as a leader in the in-
dustry it helped to father.
Today it is Eastman Super-sensitive
Panchromatic Negative that points
the way to new heights of accom-
plishment, in a new era of cinematog-
raphy. Eastman Kodak Company
(J. E. Brulatour, Inc., Distributors).
EASTMAN FILM
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
Volume XX MAY, 1933 Number 5
CONTENTS
Page
An Introduction to the Experimental Study of Visual Fatigue.
P. A. SNELL 367
Avoidance of Eye Fatigue F. H. RICHARDSON 391
RCA Victor High Fidelity Film Recording Equipment
S. READ, JR. 396
A New Process of Television Out of Doors
A. T. STOYANOWSKY 437
Book Reviews 444
Officers 446
Committees 447
Society Announcements 450
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
SYLVAN HARRIS, EDITOR
Board of Editors
J. I. CRABTREE, Chairman
L. DE FOREST A. C. HARDY E. LEHMANN
O. M. GLUNT F. F. REN WICK
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.
Publication Office, 20th & Northampton Sts., Easton, Pa.
General and Editorial Office, 33 West 42nd St., New York, N. Y.
Copyrighted, 1933, by the Society of Motion Picture Engineers, Inc.
Subscription to non-members, $12.00 per annum; to members, $9.00 per annum,
included in their annual membership dues; single copies, $1.50. A discount
on subscriptions or single copies of 15 per cent is allowed to accredited agencies.
Order from the Society of Motion Picture Engineers, Inc., 20th and Northampton
Sts., Easton, Pa., or 33 W. 42nd St., New York, N. Y.
Papers appearing in this Journal may be reprinted, abstracted, or abridged
provided credit is given to the Journal of the Society of Motion Picture Engineers
and to the author, or authors, of the papers in question. The Society is not re-
sponsible for statements made by authors.
Entered as second class matter January 15, 1930, at the Post Office at Easton,
Pa., under the Act of March 3, 1879.
AN INTRODUCTION TO THE EXPERIMENTAL STUDY
OF VISUAL FATIGUE*
PETER A. SNELL**
Summary. — Previous work has shown that fatigue of the visual process as a whole
is not directly measurable; it is therefore necessary to adopt the alternative method of
studying the individual processes involved in vision. An analysis of the studies
so far made on these unit functions shows that the motor processes involved are not
readily fatigued; ineffective activity of these processes, however, rapidly leads to sensa-
tions of fatigue. This activity results from inadequate sensory projection, whether
the inadequacy is a result of difficult external seeing conditions or of decreased efficiency
of the retinal processes. Experiments were performed which showed that: (1) the
effective intensity of a given stimulus was affected considerably by the previous activity
of the retina; (2) contrasts, and especially flicker , produced a marked retinal fatigue;
(3} the site of this fatigue lay in the retinal structures behind the sense endings rather
than in the sense endings themselves. It is concluded that retinal fatigue contributes
a larger factor to visual fatigue than has hitherto been supposed; as long as the visual
task is such that the factors producing a decrease in retinal efficiency are minimal,
as is not usually the case in viewing the motion picture, visual fatigue will not super-
vene with unusual rapidity.
At the very beginning of a consideration of the problem of visual
fatigue, it is apparent that no solution will be forthcoming until
after a prolonged attack by many investigators. The amount of
work that can be accomplished in one year is small compared with
what is yet to be done. Whatever progress can be made in this
short interval of time is valuable only in proportion to the amount
of solid foundation laid for the benefit of those who will continue
toward the solution. In order to proceed on a fundamental basis,
therefore, this study was begun and carried out along three related
lines: (1) a partial compilation of the studies so far made on visual
fatigue; (2) an analysis of some recent advances in the field of visual
physiology which are pertinent to this study; (3) the undertaking
of experimental work leading to the establishment of new facts
aiding in the further elucidation of the problem.
It is obviously desirable to agree on a meaning for the term fatigue.
* Presented at the Spring, 1933, Meeting at New York, N. Y.
** S.M. P. E. Fellow at the University of Rochester, Rochester, N. Y.
367
368 PETER A. SNELL [j. S. M. P. E.
To the layman fatigue implies the idea of physical tiredness, usually
the result of work, and includes in its connotation loss of efficiency
and lack of desire. In this sense the term is too broad for our pur-
pose. In strictly physiological nomenclature, fatigue has a much
more definite meaning. This meaning is expressed in the following
rather technical definition: "Fatigue is a metabolic state resulting
from the inability of anabolic processes to proceed as rapidly as
catabolic ones during the activity of an organ or part." This
definition puts fatigue definitely with the phenomena peculiar to
living tissues, draws attention to fatigue as a state apart from any
other state or situation of such tissues, and emphasizes the role of
activity in the establishment of the state. The definition properly
omits reference to the manifestations of fatigue, as they are rather
characteristic of the particular organ subject to fatigue than of the
state itself.
We can not consider fatigue without reference to the phenomenon
of adaptation. The above definition of fatigue is also a definition
of adaptation. One can consider that in the case of adaptation the
catabolic reaction is desirable; in the case of fatigue, it is undesir-
able. It seems that nature has made the best of the situation, and
upon occasions has turned the occurrence of the fatigue reaction to
a useful purpose. Adrian1 distinguishes somewhat more definitely
between the two in describing fatigue as a "decline in activity caused
by the previous activity of the organ," and adaptation as a "decline
in excitability caused by the stimulus — the change in the environ-
ment— quite apart from the existence of activity." This definite
distinction is not applicable to any situation, however, since in
general the state of any organ at a given time is inseparably linked
up both with its previous activity and with the stimulus existing at
that time.
Actually, there are characteristic differences between fatigue and
adaptation. (Hereafter in this discussion fatigue refers to physio-
logical fatigue.) Adaptation is a reaction which occurs immediately
following the presentation of the situation calling for it, takes place
rapidly, brings about a benefit to the organism, and, finally, has a
slight, if any, subjective effect upon the organism. Fatigue, on the
other hand, is delayed in its occurrence following the presentation
of an adequate stimulus, is slow to develop, brings about harm to the
animal economy, and, finally, has a rather profound effect upon the
organism. Yet, in spite of these differential characteristics, fatigue
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE 369
and adaptation can not be definitely and quantitatively differentiated
in any given set of conditions.
Ophthalmologists as a group are outstanding in contributions to
the study of the problem of visual fatigue, since they are in a position
to recognize its importance as well as to observe the sequence of
cause and effect in its occurrence. In his practice the ophthalmolo-
gist sees cases representative of the whole range of fatigue states,
from the simplest so-called "eye-strain" to the severe crippling
condition of asthenopia. If we examine this whole range of condi-
tions, we find that the differences between them are almost entirely
those of degree. Asthenopia, according to Jackson,2 refers to the
condition present in "those unable to use the eyes for more than a
very brief time without pain, although the eyes are without recog-
nizable ocular conditions to account for this disability." The
pain, hyperemia, lacrymation, and other symptoms and signs present
in this condition, are the same in nature and sequence as those
present in cases of eye-strain due to a simple refractive error or any
other cause. Lancaster's3 description of the symptoms and signs
occurring as a result of ocular work under faulty illumination is
practically the same as Jackson's4 account of those manifesting the
existence of visual fatigue. There is no doubt that the eye always
responds by the same fatigue reaction to any and all conditions under
which, as Lancaster has shown, seeing is a more difficult task than
the visual mechanism is prepared to handle.
Anything causing difficult seeing will result in eye-strain. In the
production of visual fatigue under conditions for seeing which are
not unfavorable, it is the decline in efficiency of the eye after a
fairly prolonged period of use which brings about the condition of
difficult seeing resulting finally in eye-strain. If the eye or visual
apparatus is exceptionally poor, average conditions for seeing are
too difficult for the eye to handle from the start, and eye-strain
appears after a very short exposure. If the external conditions for
seeing are unfavorable, even though the eye is normal or average in
ability, eye-strain will result after a fairly short interval. Luckiesh
and Moss5 have emphasized this relationship between the external
and the physiological factors in ocular function by the consideration
of seeing as "a partnership of lighting and vision."
Eye-strain which has progressed far enough to be causing sub-
jective symptoms has become truly severe. Jackson4 has empha-
sized the fact that headache and eyeache indicate the establishment
370 PETER A. SNELL [j. S. M. P. E.
of a pathological reaction rather than temporary weariness.
"Normal visual fatigue rarely rises into consciousness. Only when
the organism in response to long continued or repeated excessive
fatigue has developed a method of translating this into discomfort
or pain does it develop into symptoms that bring patients to us for
relief."
Herein lies the difficulty in finding an easy approach to the
study of this problem. We can not tell when a normal state of
fatigue has been produced, because we are not immediately conscious
of its presence nor are we conscious of the increasing effort necessary
to counterbalance it. Many attempts have been, made to demon-
strate the occurrence of normal visual fatigue by following the
changes in time necessary to perform a given task after a preliminary
variable fatiguing period, or by following changes in external condi-
tions necessary to keep the eyes working at a given pace. Some of
these experiments are extremely interesting. Luckiesh and Moss5
cite an experiment in which the time required to read a given amount
of printed matter when the page was stationary was compared with
that required when it was vibrating. The experiment showed that
although subjectively the task was quite obviously more difficult
when the page was vibrating, nevertheless the time consumed was
practically the same in both cases. Ives,6 in another experiment,
found that there was little change in visual acuity following pro-
longed visual work under poor as compared with good lighting condi-
tions. In a different type of experiment, involving a visual task
which called for prolonged use of the extraocular muscles, Cobb
showed that the ability of the subject to perform the task did not
change when a high illumination level was substituted for a low one,
although the task set elicited a severe visual fatigue.
Luckiesh and Moss5 have suggested that the failure to demonstrate
visual fatigue by these methods is due to the biological principle of
compensation. After fatigue, the body or any part of it can still
perform a given task as quickly and as accurately as before; because
it has the faculty of drawing on reserve forces only when reserves are
needed, and of conserving any energy remaining so that it will be
available for the continuance of response at the previous level. The
occurrence of visual fatigue is accompanied by greater difficulty in
seeing, not by less ability to see.
It is evident that the demonstration and quantitative measure-
ment of visual fatigue offers an unusually complicated problem.
May, 1933] EXPERIMENTAL STUDY OF VISUAL FATIGUE 371
It is possible to recognize the presence of visual fatigue, and to state
with some degree of certainty the conditions under which it is likely
to occur. It is not yet possible to explain how it is produced, what
factors underlie its occurrence, what the vulnerable points in the
visual mechanism are, nor how these points may be reached or pro-
tected. In order to increase our knowledge concerning these im-
portant questions, the prime requisite for experimental attack is a
method of measuring visual fatigue. And up to the present time
this phenomenon has taken very unkindly to association with any
form of yardstick.
Since visual fatigue as a whole appears at present impossible of
measurement, the only alternative open is the measurement of the
fatigue of the various individual processes involved in vision. The
physiological characteristics and properties of the different tissues
have been carefully studied, and their behavior is fairly well known.
It should be possible, therefore, by determining the reactions of the
individual units or unit functions to fatiguing conditions, to deter-
mine the locations, and the relative amounts of fatigue in those
locations, and their proportions to the sum total of visual fatigue.
The first step in such an attack is therefore the subdivision of the
visual process into its unit functions and structures. The accom-
panying classification has been adopted as a basis for the study of the
various parts of the visual mechanism as they individually show
themselves subject to fatigue.
The responsibility for visual fatigue has been laid at the door of
most of the functional groups enumerated above. Many of these
groups have been studied experimentally, and a large amount of
interesting and important data relative to the occurrence of fatigue
has been accumulated. A study of the results of those experiments
becomes an integral part of our immediate problem, since it is to
those findings that we must add further experimentation in order to
increase the factual basis leading to the solution of our problem.
A very prevalent idea among workers on the subject is that the
extraocular muscles are the chief offenders in the establishment of
visual fatigue. A moment's consideration will bring out the fact
that the eyes are in motion almost constantly throughout the day,
and that no matter what the occupation, they are an important and
ever-active tool. Luckiesh and Moss5 have estimated that one-
fourth of the consumption of bodily energy is due to seeing. The
number of motions made by an eye in an average day's work is of
372
PETER A. SNELL
[J. S. M. P. E.
course tremendous. On the other hand, the average amount of
motion performed by the eye does not result in sufficient fatigue to
produce perceptible symptoms. One is very conscious, for example,
of fatigue of the upper arm muscles when an attempt is made to
hold the arms outstretched for even a short length of time. In all
probability, the eye muscles are of sufficient strength to care for
the average needs of ocular motion without becoming fatigued.
It is necessary, however, to examine this question much more care-
Functional Group
Effectors — the mecha-
nisms controlling
change in the physical
modification of the in-
cident light and its
relation to the eye.
2. Receptors — the mecha-
nisms bringing about
the transposition from
physical to physiologi-
cal stimulus.
3. Conductor s — t h e
mechanisms involved
in the conduction of
the physiological
stimulus, and its elabo-
ration to the condition
of perception.
THE VISUAL PROCESS
Function
a. Accommodation (lens
changes only) .
b. Diaphragmatic func-
tion of the iris.
c. Fixation.
d. Pigment migration.
e. Movements of cones
and rods.
A natomical Structures
Ciliary body muscu-
lature.
Iris, constrictor, and
dilator muscles.
Extraocular muscles.
Hexagonal cells of the
retinal epithelium.
Cones and rods.
a. Irritability to light. Rods and cones.
a.
Conduction
ception.
and per-
Control and conduc-
tion of the stimulus
for the improvement of
perception through the
effectors of group 1.
Retina (except rods
and cones), optic
nerve, and brain.
Various cranial nerves
and brain centers.
fully in order to decide with some degree of probability what per-
centage, if any, of visual fatigue is due to fatigue of the extraocular
muscles.
Lancaster3 presents an analysis of the work done by the extra-
ocular muscles. He points out that they are much more favorably
situated in regard to their mechanical advantage than are the other
striated muscles of the body. He has calculated that the amount
of force required to move the eye through an arc of 10 degrees in
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE 373
0.04 second is equal to 1.73 grams. The power of the muscle to
overcome this load is equivalent to 750-1000 grams, so that there
is a tremendous latitude between reserve force and actual demand.
It is difficult to fatigue any muscle unless it is made to work against
a load which is severe. While there are no direct studies as yet
upon extraocular muscles, it is highly probable that such a study
would show no measurable fatigue of these muscles under a load
considerably greater than their average load. Under normal condi-
tions the extraocular muscles maintain their activity indefinitely,
by a mechanism whereby the various fibers in a muscle take turns
supporting the load so that each individual fiber works for but a
small fraction of the time; thus fatigue does not occur.
The function of the extraocular muscles is that of fixation. Lan-
caster3 believes that fixation is one of the two functions in the visual
process which are subject to fatigue. The process of fixation,
however, involves other structures as well as the extraocular muscles,
which serve only as effectors. Even if it be possible to justify the
argument against the occurrence of fatigue in the extraocular muscles,
there still remains the possibility of its occurring in the central
mechanism controlling fixation.
By photographing the eye movements, the process of fixation has
been shown to take place in two stages : first, the eyes move rapidly
to bring the object being fixated in the center of the field; then,
secondly, slow, delicate movements are made to bring the image of
the object fixated in the exact spot upon the retina where it is wanted.
During prolonged fixation upon an object, there is a constant slight
shifting necessary for the finest perception possible; occasional
gross movements also occur at intervals as fixation is maintained.
From a binocular point of view, fixation has a latitude which is
dependent upon Panum's area. Lancaster3 has shown that in
favorable conditions, as in fixating objects which are easy to see,
the eye does not make the finest adjustments of which it is capable.
The ordinary adjustments required of the eyes are not very accurate.
However, when conditions are unfavorable for seeing, as with poor
print, unsteady light, or shiny paper, the eye must adjust more
accurately in order to see as well. There is then a greater demand
on the mechanism for fixation, and it is certainly possible that under
these conditions the extraocular muscles as well as the mechanism
for fixation may contribute to ocular fatigue.
Ferree has offered the suggestion that light striking the periphery
374 PETER A. SNELL [J. S. M. P. E.
results in a stimulus tending to bring about fixation of the light source,
with consequent turning of the eyes in that direction. If the light
persists in the periphery during continued fixation of the former
object, the rivalry resulting between the two fixation positions is
a cause for the production of fatigue of the extraocular muscles.
Such a situation frequently arises. It is, however, rather more in
line with usual physiological behavior to place the site of a fatigue
arising as the result of such a situation in the central mechanism
for fixation, rather than in the extraocular muscles themselves. The
rivalry which occurs is central; the muscles can not be fatigued by
the possibility of activity which actually does not occur.
Howe7 has made a study of fatigue of the extraocular muscles
by an instrument which he calls the ophthalmic ergograph. This
instrument consisted essentially of a variable prism whose strength
was automatically recorded. It was found that the strength of the
prism which the various muscles could overcome by their action
decreased during successive attempts over a given length of time.
Experiments such as these are interesting in showing the amount
of effort necessary to elicit fatigue; they do not localize the site of
that fatigue. If the prism is so arranged that, for example, adduc-
tion is shown to become fatigued, this fatigue may occur either in
the adductor muscles, or in the central mechanism for their control,
and in the mechanism for fusion of the two images. By the nature
of the experiment, none of these possibilities are excluded.
It is justifiable to conclude that the evidence so far presented
indicates that fixation plays only a small role in general visual
fatigue, and that it is the central or nervous part of the mechanism,
rather than the extraocular muscles themselves, which is the vul-
nerable spot in the fixation process.
Accommodation has frequently been accused of much responsi-
bility in the occurrence of ocular fatigue. It is common knowledge
that those who are inclined to suffer following visual overwork fre-
quently lay the blame on reading and other forms of close work,
which differ from distance vision in the necessity for prolonged
accommodation. Accommodation, therefore, appears directly re-
sponsible. According to the generally accepted theory regarding
the mechanism of accommodation,8 the ciliary muscle is under a
greater tension when the surface of the lens is adjusted to bring the
image of near objects to a focus upon the retina; it is more relaxed,
or under less tension, when the eye is accommodated for far objects.
May, 1933] EXPERIMENTAL STUDY OF VISUAL FATIGUE 375
This condition has led students of the problem to consider seriously
the possibility that prolonged accommodation for near objects can
be fatiguing on account of the prolonged increased tension which
must necessarily be maintained by the ciliary muscle. In connection
with accommodation, the convergence of the eyes for binocular
vision introduces the problem of fatigue of the extraocular muscle
system into this question.
Berens and Stark9 made an excellent study of accommodation
fatigue using an improved form of ergograph. Their findings,
contrary to those of Howe, indicated that it was not usual to observe
recession of the near point and decrease in amplitude of excursion
within the time limit used. These experiments are extremely
interesting in that they show that under much more severe use than
is customary, the mechanism for accommodation does not break
down. It is not unlikely, however, that within this mechanism
the principle of compensation is responsible for failure to demonstrate
a breakdown. It is a well-known fact that the ciliary body is over-
developed in eyes whose refraction is hyperopic, and that in these
people eye-strain is a fairly common complaint; on the other hand,
individuals with myopic eyes, which have an underdeveloped ciliary
body, seldom complain of ocular pain. The association of these
facts can not be interpreted otherwise than as an indication that the
mechanism of accommodation and the ciliary body are far from
blameless in the production of ocular fatigue.
The diaphragmatic function of the iris enters into the process of
accommodation. The narrowing of the pupil in this connection
has for its purpose the improvement of the image by cutting off
the rays from the peripheral and less perfect regions of the refracting
media. It is a point of interest that this constriction of the pupil
is at the same time deleterious to the accuracy of the image because
of the proportionate increase in the amount of diffraction occurring
around the margins of the pupil. Cobb10 has shown that at a pupil
diameter of about 4 mm. the eye is at its maximum optical accuracy.
There are so many unknown quantities in connection with ac-
commodation that it is far too early to estimate with any degree of
probability its proportion of responsibility in visual fatigue. The
variables of lens changes, iris activity, and convergence function,
not to mention some unsolved questions concerning the mechanism
for bringing about the lens changes, all contribute to the difficulty
of an attack upon the problem.
376 PETER A. SHELL [j. s. M. P. E.
Accommodation, moreover, can not be ruled out of motion picture
fatigue on the ground that near vision is not involved, since hy-
peropia is such a common refractive error of mankind. In general,
however, the conditions present in the theater are such that very
little is demanded of accommodation. Therefore, although it is
impossible at present to make any really reasonable prediction
about accommodative fatigue, it is justifiable to adopt for the present
purpose the assumption that fatigue from accommodation is not
important in ocular fatigue resulting from viewing the motion
picture.
The diaphragmatic function of the iris in controlling the amount
of light reaching the retina is next to be considered. It is the ex-
perience of every one that on passing from a dark environment out
into the much brighter sunlight, a rather severe, sharp ocular pain
occurs. Dr. Fuchs was interested in the part which the iris mecha-
nism might play in this reaction; he performed the experiment of
comparing the sensations experienced upon passing from the dark
into brilliant light when his pupils were dilated with scopolamine
and when they were not under the effect of the drug. In the former
case he found that no pain was experienced in spite of the fact that
much more light reached the retina; he logically attributed the
difference in sensation to the fact that the pupil did not react when
under the influence of the drug, and concluded that it was the violent
contraction of the pupil which was responsible for the pain experi-
enced. This is an extremely interesting observation. The fully
contracted pupil is obviously not painful; no pain is experienced
once the adaptation to the most brilliant sunlight is complete.
What is it then that is painful?
Michaelson11 has presented in connection with an analysis of 100
cases of ocular headache, a discussion of the nervous innervation
of the iris and ciliary body. He has pointed out an analogy be-
tween this system and that of various other organs in the body which
are grouped together by Head12 as visceral-sensory mechanisms.
Michaelson comes to the conclusion that ciliary headache is the chief
type of ocular headache, and that the structures involved are analogous
to those which give rise to referred visceral pain in other parts of
the body. In the production of visceral pain, distension is, in prac-
tically all cases, the adequate stimulus. It is natural, therefore,
to assume distension as the adequate stimulus for ciliary pain. The
analogy, however, is not perfect. The pupil is not distended when
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE 377
dilated; it is under conditions exactly resembling distension when,
dilated, it is receiving stimuli for contraction. From Dr. Fuch's
experiment it is evident that these are exactly the conditions which
produce pain. It is justifiable to suspect the occurrence of perhaps
less conscious visceral-sensory pain stimuli under any condition
which involves the production of stimuli for decrease in pupillary
size or contraction of the ciliary muscles. In general, any condition
leading to increased difficulty in seeing involves the production of
stimuli for ciliary activity and pupillary constriction in order to
improve the image; consequently, difficult seeing becomes by this
mechanism an adequate stimulus for the causation of ocular dis-
comfort and pain.
The above considerations lend themselves in part to experimental
verification. Using a method similar to that of Reeves,13 it should
be possible to study the relationship of pupillary changes to difficult
visual conditions. I hope shortly to be able to undertake such a
study.
Pigment migration and movements of rods and cones can be
grouped together under the statement that it is not known how
important a role these functions play in whatever part of the visual
process they may be concerned. The chief function of these move-
ments is probably concerned with the adaptation of the retina to
different brightness levels. Arey14 has made some studies on the
question of control of pigment migration, and has found that in
some animals it is easy to demonstrate a central nervous control of
the activity, while in other cases the demonstration is not so easy.
The significance of the movements is also not well understood.
Arey interprets them as protoplasmic responses to definite stimulat-
ing agents. With the mechanism and purpose of these functions
so much in doubt, consideration of them must necessarily be post-
poned. If they play any part in visual fatigue the magnitude of
their share can not be estimated.
The question of retinal fatigue is one which has until recently not
received much consideration by investigators. Its importance,
however, has not been unrecognized. Jackson4 says, "Fatigue of
the retina and visual centers is more important than all other func-
tions connected with vision." There has as yet been no direct
attempt made to measure retinal fatigue, but there are numerous
instances in the literature of fatigue of the retinal and central type
occurring in the course of a study upon some phase of the visual
378 PETER A. SNELL [j. S. M. P. E.
process. Luckiesh and Moss15 cite an experiment in which the rate
of working was measured when the visual task set involved a fre-
quent change from light of one intensity to that of another. The
experiment brought out the loss in work done incident to the time
required for the frequent readaptation, and incidentally demon-
strated that such a situation was productive of a severe eye fatigue
as experienced by the subjects.
It is a well-known fact that contrasts are fatiguing. Jackson4
believes that contrast is one of the most important sources of fatigue,
and states that "retinal-central fatigue is increased by great differ-
ence in intensity of stimulus to which adjoining parts of the retina
are subjected." Contrast is a phenomenon involving many factors,
including not only external conditions, but also sensory, retinal, and
central nervous system functions. Granit16 has recently pointed
out that there is a retinal component in contrast, and thereby has
added a further indication toward the probability that the effect
of contrast in producing fatigue lies in the retinal-central mechanism.
Flicker is a phenomenon closely allied to contrast. Fatigue
results as readily from exposure to flicker as from exposure to simul-
taneous contrasts. While flicker has been studied very thoroughly
and the phenomenon frequently utilized in the study of visual
processes, no definite explanation has been forthcoming for the
vulnerability of the eye to this form of stimulation. Lancaster3
advanced the suggestion that the basis of fatigue from flicker was
the ineffectual attempt of the eye to produce a steady flux of energy
upon the retina ; the inability of the effector mechanism to transform
a flickering stimulus into a steady flux resulted in rapid fatigue of
that mechanism. While such a process is important, it can not be
considered as more than simply contributory to contrast fatigue;
in the light of recent work it appears that the retinal factor is the
most important.
While contrast fatigue is not the only form of retinal fatigue, it
is by far the most important, and the most representative of retinal
behavior. The retina as a sense organ is peculiar in that adaptation
plays a larger role in its function than in that of any other organ.
Consequently, the retina is not suited for a quantitative interpreta-
tion of stimulation. It is commonly said that the "eye can equate
but can not appraise." If contrasts were entirely removed from
our field of vision, it would be almost impossible for the eye to de-
termine whether our surroundings were bright sunlight or total
May, 1933] EXPERIMENTAL STUDY OF VISUAL FATIGUE 379
darkness. The study of contrast behavior is thus the most im-
portant method of studying visual function.
The recent studies of Granit16 and others have emphasized the
importance of the peripheral or retinal share in the analysis of visual
sensation, and have helped to focus attention upon the retina as
playing probably a much greater part in the analysis and inter-
pretation of impulses coming from the sense endings than has hitherto
been suspected. Sir John Parsons,17 in 1925, pointed out the in-
creasing evidence for complexity of retinal behavior, and stated
that the duplicity theory would prove to be too great a simplification
of retinal physiology. The newer work is amply bearing out his
predictions.
In the light of the new knowledge of retinal function, the question
of fatigue occurring in this organ becomes one of unusual interest.
In the course of the present study, it appeared that of the many
phases of the problem of visual fatigue awaiting experimental attack,
none was as important as that of the part played by the retina in
general visual fatigue. The experimental work was therefore
planned as an attack upon the problem of demonstrating the oc-
currence of retinal fatigue, together with an attempt to estimate
quantitatively its importance as compared with fatigue of other
parts of the visual mechanism.
EXPERIMENTAL
In the last ten years there have been many advances made in our
knowledge of the behavior of sense organs in general. Adrian19
has shown that all forms of peripheral sensitivity depend on func-
tional units whose behavior is basically similar. For the sense of
sight, he has shown that this basic behavior is modified so that the
demonstrable changes in the eye and optic nerve are complicated
by the interposition of the retina; therefore he was able to study the
part played by the retina in the elaboration of the stimuli from the
light sense endings. Granit18 demonstrated that phenomena char-
acteristic of central nervous system behavior could be shown to occur
in the retina, and that therefore the retina could properly be called
a true nervous center. The experimental work of Adrian and Granit
on the eyes affords a basis for the experimental attack on the question
of retinal fatigue.
Adrian showed in his studies on the eel's eye that the total effect
of light falling on the eye was transmitted to some region whose
380 PETER A. SNELL [j. S. M. P. E.
extent was independent of the area illuminated. In addition, he
found that under certain conditions a rhythmical discharge occurred
in the optic nerve as a result of action in unison of the ganglion
cells in the retina. Furthermore, he showed that when four separated
regions on the retina were illuminated simultaneously, the reaction
time was shorter than when one was illuminated alone; this inter-
action between distant retinal areas was enhanced by the addition
of strychnine to the prepared anatomical specimen, a drug which by its
action decreases synaptic resistance. These experiments, therefore,
demonstrated among other findings the presence of an interaction
taking place in the retina as a fundamental part of its reaction to
simple stimuli.
Granit16 demonstrated the occurrence of interaction in the human
eye by adapting Adrian's experiment to a subjective method. Using
critical frequency as a criterion for the effective intensity of a stimu-
lus, he showed that the effective intensity of a given stimulus was
lower when the stimulus was presented alone than when presented
simultaneously with stimuli falling on other parts of the retina.
In further experiments he studied the relationship of interaction
to retinal behavior, and showed that many of the properties of the
visual mechanism were bound up with retinal reactions of the synap-
tic type.
Granit considers that, for any given amount of activity in a func-
tioning group of ganglion cells, part of this activity results from
activity beginning in receptors directly in front (distal) of the gang-
lion cells, and part is the result of activity coming via association
fibers from sense endings lateral to the active cells. Any given spot
of activity in the ganglion cells thus has an effective intensity which
represents the sum of input over frontal and lateral channels. By
the proper selection of differing types of stimulus, therefore, it is
possible to distinguish between frontal and summative responsibility
for changes in effective intensity. Granit demonstrated by this
method that the site of adaptation lay in the sense endings rather
than in the synaptic mechanism.
This method is well suited to the purpose of localizing the oc-
currence of retinal fatigue. By its use it should be possible not only
to determine whether any fatigue occurs in the retina, but also to
assign a semi-quantitative value to the various factors concerned
in the causation of the fatigue.
The apparatus finally adopted was a compromise between the
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE
381
ideal and one which, while suited to the various types of experiment,
could be constructed with the minimum of delay. As a source of
illumination, a standard projection lamp was used, mounted in a
suitable lamp house. The optical system consisted of the usual
condenser lenses and projection lens, so arranged that the plane of
the image of the lamp filament was a few centimeters in front of the
projection lens. In this plane was placed a rotating sector disk,
so that when the sector disk was rotating, movements of the image
of the diaphragm on the screen were negligible. The arrangement
is illustrated in Fig. 1. The size and shape of the image on the
D
NOV. D.C.
FIG. 1. Diagram illustrating the apparatus used for determining ocular
fatigue: 1, lamp control resistance ; 2, lamp circuit ammeter; 3, lamp cir-
cuit voltmeter; 4, projected slit; 5, sector disk; 6, disk motor control re-
sistance; 7, Western Electric tachometer; 8, tachometer voltmeter ; 9, screen;
10, subject.
screen were controlled by the use of different diaphragms; the
intensity of illumination was varied by a resistance in the lamp
circuit. This method is sufficiently accurate for the comparatively
narrow range over which the variations were made. The actual
intensity on the screen was measured for the different lamp amperages
with a Macbeth illuminometer.
In actual practice, the subject was seated 20 feet from the screen.
A preliminary period of adaptation to a very low level of illumina-
tion, lasting 20 minutes, preceded every experiment. Both eyes
of the subject were always exposed to the fatiguing stimulus; the
critical frequency determinations were made on the right eye. In
taking the readings, an attempt was made to obtain the point at
which flicker just appeared in at least 6 seconds, since this is con-
sidered the approximate length of time during which the eye can
382
PETER A. SNELL
[J. S. M. P. E.
fixate a given point without moving. If more than 6 seconds proved
necessary, the reading could usually on the next attempt be made
within that time, since the approximate value was then known.
The speed of rotation of the sector disk was varied by a resistance
in the armature circuit of the motor, and the rpm. indicated by a
Weston tachometer. One sector disk was used for all the critical
frequency readings.
The experiments were begun by determining the critical frequency
curves for the normal eye. The curves were plotted for only two
different areas of stimulation, since these two are all that are neces-
sary. Fig. 2 shows the curves of four subjects for a stimulation area
60
cJ50
LJ
LU
Q.
1
^30
20
.4
1.6
2.0
FIG. 2.
.8 1.2
LOG. OF I
Critical frequency curves for four subjects, for stimulation area of
four degrees' diameter.
of 4 degrees of diameter; there is apparent a marked difference in
sensitivity to flicker between different individuals, though all sub-
jects show the usual logarithmic relationship between intensity and
critical frequency.
The critical frequency for any given stimulation varies not only
with the condition of the eye as a result of previous activity of the
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE
383
eye, but also with the general condition of the subject. It was
found that in order to obtain reproducible results, it was necessary
to demand of the subjects that they always retire early the evening
before, and that they do no reading before coming to the laboratory
the next morning. Not more than two hours could be utilized in
any one day, since readings made over a longer period of time or in
the afternoon showed greater variability than those taken in the
early part of the day.
The method for demonstrating and localizing the retinal fatigue
o
u
to
UJ
a
\^
A^-4 —
.4
.8
1.2
LOG. OF I
1.6
2.0
FIG. 3. Critical frequency curves derived from the curves of Fig. 2, for dem-
onstrating the localizing of retinal fatigue.
depends on the fact that interaction plays a proportionately greater
role in bringing about a given effective intensity as the area of the
retina stimulated is increased. From the critical frequency curves
of the subject, three points are chosen, as shown in Fig. 3. These
points are so related that points A and C have the same area but
different intensities, C and B the same critical frequency (effective
intensity) but different areas, and A and B the same intensity but
384 PETER A. SNELL [j. S. M. P. E.
different areas. C has the same critical frequency as B in spite of its
lower intensity, because of its greater amount of interaction. A owes
a larger percentage of its effective intensity to interaction than does
B, because of its larger area.
In practice, the subject observed the screen for half an hour,
while a slowly flickering light was projected thereon. During the
half hour, five readings of the critical frequency were taken for one
of the three "crucial points," A, B, or C; the points were presented
either at random or in rotating order. Half-hour runs were also
made with readings for the same point taken throughout. No read-
ing was ever taken at twenty-five minutes in order to avoid any effect
on the value at thirty minutes, although it was found that the break
in the fatiguing stimulus necessary to take a critical frequency read-
ing had a negligible effect on the subsequent readings. Since many
experiments were therefore necessary to obtain the essential data,
those points for which one check was obtained were included in the
results; it would be better from a statistical point of view to include
many readings and calculate the mean of the values obtained, but
time was not available. Moreover, a more exact determination of
the absolute values for the critical frequency is superfluous in view
of the fact that other variables in the factors involved in the ex-
periment can not be controlled within a variability range as small as
that represented by the values for critical frequency obtained by
the above method.
The analysis of the readings is shown in Fig. 4. For each of the
three "crucial" points a curve is plotted showing the course of the
critical frequency change with time. On the same graph is plotted
a curve obtained in exactly the same manner as the first except that
the "fatiguing" stimulus was not flickering. The difference between
the two curves represents the fall in effective intensity resulting from
the flicker characteristic of the stimulus. It therefore represents
a true flicker fatigue.
Table I presents a summary of the results for the three subjects
upon whom a complete set of readings was obtained. Subject
T.N. showed the greatest susceptibility to flicker fatigue. The
table shows that in one-half hour point A fell to an effective intensity
of 10 per cent of the original value; while at the same time points
B and C fell to 30 and 28 per cent, respectively, of their former
levels. Thus A , with the largest proportion of its effective intensity
due to interaction, fell the most; C and B, with relatively much
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE
385
less of their effective intensity due to interaction, C because of less
intensity than A, and B because of less area, have fallen much less.
The other subjects show the same relationship between the three
UJU
00
£45
CL
C/5
UJ Ar\
1
>48.6
^
\ 4> i
Y A-LARGE ARE;
\HIGH INTENS
ITY
r«u
CO
<
•T1^
^
(
,36.6
10 20 30
MINUTES
40
K4U
CO
tf *K
uj 35
a.
CO
u30
to
<
H9S
K
'39.3
B-
SMALL
1 <
. ARE;
>34.0
(^
HIGH ir
4TENSITY
1
10 20 30
MINUTES
40
UJ
(O
C^oc
uj35
CL
co
^30
CO
i-,
\
•jaj
N
— C-
L(
T^ f
LARGE
)W IN
— ^^— — — <
: ARE
TENS
•32.6
A
TY
10 20 30
MINUTES
40
FIG . 4. Analytical curves showing the
change of critical frequency with time;
one curve for each of the "crucial"
points of Fig. 3.
points, although not quite to the same degree. Therefore, it can
be concluded that flicker fatigue takes place in the retinal -structures
behind the sense endings rather than in the sense endings themselves.
386 PETER A. SNELL [j. s. M. P. E.
TABLE I
Summary of Experiments on Localization of Retinal Fatigue
Per Cent of
Inten-
C.F.
C.F.
E.I.
E.I.
Original
Subject
Point
Area
sity
Start
V* Hr.
Start
V« Hr.
Intensity
T.N.
A
4
High
48.6
36.6
48.0
4.8
10
B
1
High
39.3
34.0
48.0
14.8
30
C
4
Low
39.3
32.6
8.0
2.2
28
H.B. A 4 High 44.6 40.0 19.1 7.6 39
B 1 High 37.3 34.6 19.1 11.0 57
C 4 Low 37.3 34.0 4.6 2.5 54
P.S. A 4 High 53.0 41.3 42.0 7.2 17
B 1 High 41.3 36.0 42.0 11.0 26
C 4 High 41.3 33.3 7.6 2.3 30
The percentages given above represent definite values only for
a given experiment. While they serve to differentiate quite clearly
between the possible sites involved in the reaction, they are in no
wise to be considered as representing the absolute value for the fatigue
occurring at that site. It is not yet possible to estimate the absolute
percentage of frontal and lateral contributions to the effective in-
tensity of any excited area. Moreover the location of the stimulated
area is of importance in determining the amount of interaction in
the response. Therefore, the figures obtained represent only a
semi-quantitative value for the local fatigue; they nevertheless
demonstrate clearly the occurrence of retinal flicker fatigue and fix
the responsibility for most of it upon the synapses.
Table II shows the effect of rate of flicker in the fatiguing stimulus
upon the effective intensity. Not enough data were obtained to
draw any very definite conclusions, but it is evident that as long as
flicker is apparent fatigue occurs. When the rate of flicker is such
that it is not apparent, there is no fall in critical frequency during
the half-hour period.
TABLE II
The Effect of Rate of Fatiguing Flicker upon Effective Intensity
Rate of stimulus 13 . 3 26 . 6 53 . 3
C.F. E.I. C.F. E.I. C.F. E.I.
Before exposure 40.6 10.0 40.6 10.0 40.6 10.0
After Y2 hour 34.0 2.9 34.6 3.17 40.6 10. 0
May, 1933 ] EXPERIMENTAL STUDY OF VISUAL FATIGUE 387
DISCUSSION
The fact that fatigue from flicker depends on the perception of
the flicker rather than upon the absolute rate of alternation is ex-
tremely important. These two factors are of course intimately
related; the preliminary experiments show, however, that it is the
subject's sensitivity to flicker which will determine whether fatigue
results from exposure to a given flickering stimulus. This finding
is related to the fact brought out by Grunbaum20 that it is the ratio
of time of constancy of stimulus to time of changing stimulus which
has the greatest effect on the absolute value of the critical frequency
rather than the rate of rotation of the sector disk. No attempt was
made in these experiments to explore the relationship between
flicker fatigue and sector dimensions; it is probable that the rela-
tionship will be found to be closely parallel to that of perceptibility
of flicker with sector dimensions.
The curves showing the relation of effective intensity changes to
exposure to non-flickering light indicate that very little effect resulted
from such a stimulus. This relationship is a consequence of the
conditions under which the experiment was performed. Lythgoe
and Tansley21 have recently brought out the fact that during ex-
posure to light the critical frequency due to rod activity falls, while
that due to cones rises. The type of response is determined by the
illumination level of the surroundings. In these experiments, the
background illumination level and the size of the screen were such
that very little change in adaptation level occurred. Some of the
curves do show a slight tendency toward an increase in the critical
frequency during exposure to the steady stimulus, which is the type
of change to be expected since the experimental conditions are such
that cone responses are chiefly concerned.
Flicker is, of course, not the only environmental condition which
elicits retinal fatigue. Any type of stimulus will bring about the
same kind of retinal fatigue in proportion to the amount of synaptic
activity involved in the retinal response. The ordinary activities
of every-day life all produce a certain amount of retinal fatigue which
can be detected by the method used in this investigation. When one
of the subjects inadvertently read the morning newspaper before
coming to the laboratory, the absolute critical frequency levels were
depressed more than 10 per cent. Another subject made the mistake
of spending some time in drawing, with the result that this more
severe visual task left his retina in a measurably depressed state
388 PETER A. SNELL [j. s. M. p. E.
more than three hours afterward. The depression of retinal response
by normal activity is a real fatigue in the physiological sense; the
fatigue must progress close to the point of exhaustion before it can
intrude into consciousness and cause symptoms.
Finally, it may be profitable to consider briefly the present status
of the question in connection with the motion picture. As a visual
task, viewing the motion picture is essentially similar to all other visual
tasks; the amount of involvement of the various functions of the
visual process is modified by the factors of discontinuous stimulation,
dark adaptation, and continuous accommodation for far incident
to this particular form of visual work. The high degrees of contrast
present and the discontinuous nature of the stimulus have both
been shown to be important causes of retinal fatigue and consequent
decrease in ability to see.
In Table III is presented an estimate of the relative importance of
the various functions of the visual process involved in motion picture
fatigue. The figures are to be considered as representing only the
probable values; they are not based on any accurate quantitative
TABLE III
Estimate of the Probable Proportions of Responsibility of the Functions of the Visual
Process in the Production of Visual Fatigue by the Motion Picture
Function Per Cent
Accommodation (lens) 10
Diaphragmatic function of the iris 10
Fixation 10
Pigment migration and movements of rods and cones 0 (?)
Irritability to light (including adaptation) 5
Conduction and perception
a. Retinal 40
b. Central 15
Control of effectors 10
experiments, and are presented in the nature of a summary of the
above discussion. The retina has been shown to be particularly
susceptible to contrast fatigue, especially perceptible flicker. The
effectors, particularly those of the uveal tract, are unable to improve
the image sufficiently to compensate for the decreased efficiency of
the retina; it has been shown that there probably exists a mechanism
for translating the futile excessive efforts of the effectors into un-
comfortable sensations and even pain. As long as the fatigue can
be kept within the usual limits of other every-day visual tasks, the
May, 1933] EXPERIMENTAL STUDY OF VISUAL FATIGUE 389
existence of the fatigue will not make itself known. When this is
the case, viewing the motion picture will be no more fatiguing than
any other activity of the organs of sight.
ACKNOWLEDGMENT
This work was carried out under a fellowship of the Society of
Motion Picture Engineers at the Institute of Applied Optics, Uni-
versity of Rochester. I am deeply indebted to the members of the
staff for their valuable assistance and cooperation during this in-
vestigation, and especially to Mr. Gustave Fassin, who assisted
materially in the design and construction of the apparatus which
was employed.
REFERENCES
1 ADRIAN, E. D. : "The Basis of Sensation," W. W. Norton & Co., New York,
1928.
2 JACKSON, EDWARD: "Asthenopia," Amer. J. Ophth., 4 (1921), p. 218.
3 LANCASTER, W. B.: "Eye Strain and Ocular Discomfort from Faulty
Illumination," Annals of Ophth., 23 (1914), p. 250. "Ocular Symptoms of Faulty
Illumination," Amer. J. Ophth., 15 (1932), p. 783.
4 JACKSON, EDWARD: "Visual Fatigue," Amer. J. Ophth., 4 (1921), p. 119.
5 LUCKIESH, M., AND Moss, F. K. : "Seeing — A Partnership of Lighting and
Vision," Williams & Wilkin Co., Baltimore, 1931.
6 Ives, I. E.: "Studies in Illumination," U. S. Public Health Bulletin, No. 181.
7 HOWE, LUCIEN: "The Measurement of Fatigue of the Ocular Muscles,"
Trans. A. M. A., Sec. on Ophth. (1912), p. 423.
8 LUEDDE, W. H.: "The Mechanism of Accommodation: Facts and Fancies,"
Arch. Ophth., 7 (1932), p. 40.
9 BERENS, CONRAD, AND STARK, E. K.: "Studies in Ocular Fatigue," Amer.
J. Ophth., 15 (1932), pp. 216, 527.
10 COBB, P. W.: "The Influence of Pupillary Diameter on Visual Acuity,"
Amer. J. Physiol., 36 (1915), p. 335.
11 MICHAELSON, I. C.: "Angina Capitis," Brit. J. Ophth., 16 (1932), p. 202.
12 HEAD, HENRY: "On Disturbances of Sensation with Especial Reference to
'the Pain of Visceral Disease," Brain, 16 (1893), p. 1; Ibid., 17 (1894), p. 33;
Ibid., 19 (1896), p. 153.
13 REEVES, P.: "The Response of the Average Pupil to Various Intensities of
Light," /. Opt. Soc. of Amer., 4 (1920), p. 35.
14 AREY, LESLIE B.: "The Function of the Efferent Fibres of the Optic Nerve
of Fishes," /. Comp. Neurol., 26 (1916), p. 213. "The Movements in the Visual
Cells and Retinal Pigment of the Lower Vertebrates," J. Comp. Neurol., 26
(1916), p. 121.
15 LUCKIESH, M., AND Moss, F. K.: "The Rate of Visual Work on Alternating
Fields of Different Brightnesses," /. Frank. Inst., 200 (1925), p. 731.
16 GRANIT, RAGNAR: "Comparative Studies on the Peripheral and Central
Retina," Amer. J. Physiol., 94 (1930), p. 41; Ibid., 95 (1930), pp. 211, 229.
390 PETER A. SNELL
GRANIT, RAGNAR, AND DAVIS, W. A.: Ibid., 98 (1931), p. 644. GRANIT, RAGNAR,
AND HAMMOND, E. H.: Ibid., 98 (1931), p. 654. GRANIT, RAGNAR, AND GRAHAM,
C. H.: Ibid., 98 (1931), p. 664.
17 PARSONS, SIR JOHN: Bowman Lecture, "The Foundations of Vision,"
Lancet, 2 (1925), p. 123.
18 GRANIT, RAGNAR: "The Retina as a Nervous Center," Arch. Ophth. N. S.,
6 (1931), p. 104.
19 ADRIAN, E. D., AND MATTHEWS, R.: "The Action of Light on the Eye,"
J. Physiol., 63 (1927), p. 378; Ibid, 64 (1928), p. 279; Ibid., 65 (1928), p. 273.
20 GRUNBAUM, O. F. F.: "On Intermittent Stimulation of the Retina," /.
Physiol., 21 (1897), p. 396.
21 LYTHGOE, R. J., AND TANSLEY, K.: "Regional Variation in Sensitivity to
Flicker," Proc. Royal Soc., Series B, 105 (1929), p. 60.
AVOIDANCE OF EYE FATIGUE
F. H. RICHARDSON**
Summary. — The author discusses various defects in the production and pro-
jection of motion pictures, upon -which the occurrence of ocular fatigue is assumed
to depend. Remedies for these defects are suggested and the effect upon the patronage
of a theater by the failure to apply the remedies is noted.
Much has been written concerning the alleged straining of eyes
incident to the viewing of motion pictures. Many who had little
knowledge of the real facts of the matter have declared such strain
to be severe; they have succumbed to the common fallacy of basing
their conclusions upon inadequate data, and have failed to differ-
entiate between the effects of viewing motion pictures that have
been properly assembled and properly projected, and of viewing
pictures that have been marred by avoidable and entirely unnecessary
defects, which shall here be described.
A properly assembled picture, properly projected in a properly
illuminated auditorium, places upon the eyes a burden that is little
if any greater than that of reading ordinary book or newspaper print
for an equal length of time.
However, it must be remembered that in the modern motion pic-
ture theater the viewing time is quite long. The eyes of the patrons
are used continuously for the entire length of the show; and on that
account every possible effort should be made to make the work that
the eyes have to do as easy as possible. If all unnecessary abuses
and eye shocks were eliminated, then little or no ocular fatigue would
occur.
However, it must be admitted that the matter of avoiding eye-
strain has been very lamentably and inexcusably neglected. It is
the purpose of this paper to point out the nature of the various
defects that lead to ocular fatigue and to suggest remedies for them.
In theaters, the chief cause of eye strain that lies wholly under the
* Presented at the Spring, 1933, Meeting at New York, N. Y.
** Motion Picture Herald, New York, N. Y.
391
392 F. H. RICHARDSON [j. s. M. P. E.
control of the projectionist and the theater manager is lack of defini-
tion in the screen image, due to the failure of the projectionist to
focus the projection lens properly. This occurs particularly in
theaters in which the projection distance is quite great, as it is then
impossible for the projectionist to determine with the naked eye
whether the sharpness of focus is optimum nor not. The projec-
tionist should always be able to examine the screen image through
a high-power double glass, held rigidly in a fixed position so as to be
always available for instant use.
This is an accessory essential to good work. It is important even
in theaters in which the projection distance is short; but it is rarely,
if ever, found in theaters. Common sense should tell us that the
projectionist should be able to examine the screen critically and
frequently. He can not examine it critically with the naked eye;
and he is further handicapped by the fact that in modern theaters
the observation port is invariably covered with glass, usually set at
an angle to the surface of the screen.
It is quite true that a few theater managers provide an opera
glass of greater or less power. However, a glass that is not fixed in
position is quite inadequate; usually it is deposited at the most
convenient point by the man who used it last, and when wanted
must be sought for. As a consequence, it is not used as often as it
ought to be. Moreover, the screen usually is examined through
the glass cover of the port. But in any event, a glass capable of being
moved is of little value because the projectionist can not hold it
steadily enough in his hands to permit him to examine critically
the lines on a distant screen.
Two other causes of poor definition, which are within the control
of theaters, are the presence of oil on the film, which is a matter for
theater managers to take up with exchanges, as well as to make sure
that oil is kept from the films while in the theater ; and the presence of
dirt on the projection lenses. It should be the duty of the pro-
jectionist to keep the lenses perfectly clean.
The next cause of fatigue of the eyes to be considered is travel
ghost, either in sufficient amount to be obvious, or in so small an
amount as to be visible only by observers near the screen; or, even
then, visible only through an opera glass. Travel ghost is seen in a
surprisingly large number of theaters, for the simple reason that the
projectionist neglects to go down front, at least once a week, to ex-
amine the screen image critically. A point approximately twenty-
May, 1933] AVOIDANCE OF EYE FATIGUE 393
five feet from the screen is the best position from which to examine
the image when using an opera glass.
Many persons, including some able projectionists, contend that
when travel ghost is so faint as just to admit of detection, it can
cause no harm. This is a wrong conclusion. Travel ghost in any
amount tends to blur the horizontal lines of the screen image, pro-
ducing upon the eyes an effect similar to that produced by a slightly
blurred carbon copy of typewritten matter: even the best carbon
copy is never as easy to read as the original.
Another cause of eye-strain, and a very important one, may be
attributed to glare spots, the evil effects of which are, or should be,
too obvious to require much discussion. The theater manager who
permits a glare spot to exist within view of his audience, or any
portion of the audience, is evidently inconsiderate of his own interests,
and is ignorant of the seriousness of such a procedure. By way of
definition : a glare spot is any spot of white light of greater brilliancy
than the general illumination of the auditorium (other than the
screen, of course), in the field of view of the patrons looking
at the screen. A white frosted electric light bulb, white frosted light
bowl, or an indirect lighting fixture located within the field of vision
as one views the screen is a glare spot, and may be highly objection-
able. A spot of colored light may, if of sufficient brilliancy, be a glare
spot, even though, perhaps, a less serious one.
It is idle to assume that glare spots do not operate to decrease box
office income. If after the show the patrons' eyes feel uncomfortable,
or if the patrons are troubled with a slight headache superinduced
by eye-strain, they are not as likely to visit the theater again as
soon as they otherwise might. Although the patron is seldom able
to place the blame where it belongs, he attributes his fatigue to the
picture, not knowing or realizing that it was not the screen image but
a spot of light — a glare spot — that caused his discomfort.
The remedy is obvious: eliminate glare spots. Illuminating the
auditorium exactly as for a show, let the manager view the screen
from various parts of the auditorium. If from any seat a white light
is visible, let it be removed, or made less conspicuous. If, for any
reason it is impracticable to eliminate it wholly, by extinguishing
the light, let the portion that is visible to the audience be heavily
tinted, preferably amber.
Too intense illumination of the screen may cause eye-strain for one
portion of the audience; or, with insufficient illumination, another
394 F. H. RICHARDSON [j. s. M. p. E.
portion of the audience may suffer the strain — a condition that occurs
in theaters in which the viewing distance from the rear is very great.
In such auditoriums, if a picture of reasonable size, which can be
viewed comfortably from the front seats, be projected, intense
illumination of the screen will be necessary to enable those seated
at the rear to see the details of the picture with comfort, or even to
distinguish them. However, if the brilliancy be sufficient for those
seated at the rear, it will be too intense for those seated at the front,
and may cause them to strain their eyes, particularly if other diffi-
culties, which will now be discussed, are present.
None of us is yet able to say with confidence just what the in-
tensity of light reflected from motion picture screens should be.
That is a question that involves rather grave difficulties and many
investigators have been trying to answer it for a long time. The
Projection Practice Committee now is working on the problem,
with hope of at least some degree of success.
The chief possible causes of eye-strain involved in viewing motion
pictures that are more or less under the control of the theater manager
and the projectionist have been discussed. Attention will now be
directed to perhaps the worst cause of all, over which neither pro-
jectionist nor manager has any control whatsoever. That it exists
is indisputable ; an.d that it occurs to a greater or less extent in every
picture produced must be admitted. The remedy is in the hands of
the producers, directors, cinematographers, and film editors.
It is well known that in the human eye the quantity of light ad-
mitted to the retina is, within limits, automatically controlled;
and that the adaptation of the eye to changing levels of illumination
often requires an appreciable length of time. Sudden changes
of intensity of illumination, occurring faster than adaptation proceeds,
place a burden on the seeing process that may lead to considerable
ocular fatigue. The greater the change of intensity, the longer the
time required for complete adaptation.
It is evident, therefore, that so far as is possible, sudden changes
of screen illumination should be avoided; but although the intensity
of the projector light scource and the optical system of the projector
remain unchanged, the quantity of light that reaches the screen
varies constantly, often instantaneously and in extreme amounts.
Although this fact is very apparent, even to laymen, it has been
almost utterly disregarded by those who make and assemble our
motion picture productions; who seem to ignore the fact that
May, 1933] AVOIDANCE OF EYE FATIGUE 395
instantaneous transitions from the dim lighting of a dense scene to
the full glare of an almost white screen is objectionable. Every
production provides one or several examples of such a transition.
Assume a dense interior scene, in which appear two persons, one
of whom hands to the other a letter to read; instantly the illumina-
tion of the screen changes from a very low intensity to that of prac-
tically the blank screen. It needs no argument to prove that such a
sudden change causes a "shock" to the eyes of all those viewing
the screen. In order to avoid such a state of affairs, the letter or
message could be shown as in white letters on a dark gray back-
ground, or as black letters on a lighter shade of gray. The shock
would thus be very materially reduced, and the message be made
not only as legible, but more so, because until the eye recovers from
the shock and adjusts itself to the new level of illumination, its
ability to read the message without straining itself to do so will be
much less than normal.
"But," the producer will protest, "it would be unnatural to show
a letter on other than white paper, written with other than black
ink."
Quite true; however, producers often do incorporate things not
exactly natural in their productions. For example, how often have
we seen the feminine "star" made up and beautifully attired, emerge
from the water into which the plot had driven her, with her attire
in perfect order — an effect that is admittedly unnatural. In order
to conform to the nature of things, the "star" would have to emerge
from the water in a damp and bedraggled condition.
Such letters and written messages constitute only one, though
usually the worst cause of abuse of the eyes of theater patrons.
How often do we see dense scenes followed by scenes that are much
less dense. For example, an interior, or a scene in the woods, followed
by a marine view shown brilliantly on the screen. The change from
a brilliant scene to a dense one causes little if any harm ; but a change
in the opposite sense does. The difficulty could be avoided with rela-
tively little additional trouble on the part of the directors and cine-
matographers. The instructions are : "At the beginning of a brilliant
scene which is to follow a dense one, let the scene be underexposed
and gradually brought up to normal." Certainly such a procedure
would provide an interval of time during which the eye could adjust
itself to the change of illumination without noticeable strain.
RCA VICTOR HIGH FIDELITY FILM RECORDING
EQUIPMENT*
SIDNEY READ, JR.**
Summary. — An illustrated description is given of new sound recording equipment
having an extended frequency range1 and capable of making recordings and re-
recordings on either 35- or 16-mm. film. Contact prints made from the 35-mm.
recordings or re-recordings, when played on a reproducing equipment having a
flat response characteristic, produce sound outputs that do not vary more than plus
or minus two decibels over the frequency range 50 to 9000 cycles. The equipment
is composed of units that are light in weight, are small and compact but rugged,
consume little power and are easily installed and operated for either studio or portable
use.
Some of the features of the equipment are (a) symmetrical variable width recording
with improved ground noise reduction; (&) a new large mirror galvanometer; (c)
permanent magnet ribbon microphones operated remotely from their amplifiers;
(d) improved constant impedance mixer using variable bridged "T" type attenuators;
(e) correction for the response of the human ear to speech reproduced at greater than
normal volume; (/) new amplifying equipment providing improved quality and
quieter operation; and (g) new high-quality film phonograph and recorders.
With previous types of recording equipment, about 6000 cycles
was the upper limit of uniform output when measured on a uniform-
response reproducing equipment. Even at that frequency, con-
siderable compensation was required to counterbalance the losses
in the system, including processing losses. The frequency response
was subject to considerable variation due to the mechanical resonance
of the recording galvanometer or vibrator, the cavity resonance of
the condenser microphone, and the location of the microphone
in the sound field. The height of the mechanical resonance peak of
the galvanometer was very difficult to maintain constant, due to the
change of damping with the temperature, age, etc. The frequency
characteristic of the condenser microphone varied considerably,
depending upon the angle of incidence of the sound waves. With
these variations, it was very difficult to maintain good response
* Presented at the Spring, 1933, Meeting at New York, N. Y.
** Engineering Department, RCA Victor Co., Camden, N. J.
396
RCA VICTOR RECORDING EQUIPMENT 397
even up to 6000 cycles. The problem became more involved when
re-recordings were made, especially when it was desired to combine
or mix the outputs of one or more microphones with that of a film
phonograph. It was necessary to compensate either for the micro-
phones or for the film phonograph in order to obtain similar fre-
quency characteristics; at the same time, it was necessary to main-
tain the correct over-all compensation. Due to these difficulties,
the degree of compensation and the methods of obtaining it varied
greatly from one equipment to another; and, in the case of re-
recording, varied between different films. In any case, it was usually
left to the discretion of the recordist.
Recent improvements in the quality of sound reproducing equip-
ment have furnished an added incentive to improve the quality of
sound recordings. It is always desirable that the quality of sound
recordings be superior to that of the reproducing equipment, because
sound from old recordings often is "dubbed" or re-recorded into
current productions.
The film phonographs usually consisted of slightly revised standard
reproducing sound-heads. This type of unit did not provide the
same constancy of film speed as the recorder did, and thereby caused
unnecessary distortion. Furthermore, these units abraded the film
considerably.
The unusually rapid increase in popularity of 16-mm. sound-film
recordings, both in industry and in the home, has provided a new
field for recording, which, though new, is closely related to 35-mm.
recording. It is to be expected that a large part of the 16-mm.
sound film will be re-recorded from the master positive or from
prints of standard 35-mm. sound recordings, as this provides a
very economical means of obtaining good quality 16-mm. sound
film.
It is the purpose of this paper to describe a sound recording equip-
ment that was designed for practical operation, keeping in mind
these considerations as well as others advanced by a number of
studios using previous types of equipment. Some of the advantages
of this equipment are as follows:
Recordings or re-recordings, or combined recordings and original
recordings may be made without altering the high-frequency com-
pensation. The output from a contact print of the recorded film,
when played on high fidelity reproducing equipment, is a faithful
reproduction, within plus or minus two decibels over the frequency
398 SIDNEY READ, JR. [j. s. M. P. E.
range 50 to 9000 cycles, of the original sound or of the output of the
film from which the re-recording is made.
The operation of the equipment is greatly simplified. Consider-
able simplification in operation results from compensating entirely
in one unit, which is common for recording and re-recording, the
response of all the remaining units being essentially constant over
the frequency range that it is desired to cover. This makes it
possible to record or re-record without the usual difficulty of varying
the compensation. The compensator panel, the unit that provides
the necessary correction for losses sustained in processing, has only
three degrees of compensation: namely, (1) for 35-mm. recording
or re-recording; (2) for 16-mm. recording or re-recording; and (3)
uniform response to provide for testing. A three-position switch,
suitably designated, is provided for selecting the degree of com-
pensation.
Compensation is provided to correct for the change in frequency
response of the ear with an increase in sound intensity. As speech
is nearly always reproduced at levels higher than the original, this
compensation consists in attenuating both the low and the extremely
high frequencies. Thus the recorded speech may be amplified to
the level required in the theater without changing its quality. A
switch on the microphone mixing panel provides for controlling the
attenuation while speech is being recorded. This compensation is
entirely independent of the compensation for processing losses pre-
viously referred to. The latter is required for recording all sounds,
while both are required only when recording speech or other low
level sounds.
Flexibility is improved, as regards the location of the units relative
to one another. This is accomplished by making the impedance of
the coupling lines between all units of such a value as to permit an
appreciable distance between the units with a negligible change in
frequency characteristic.
All the amplifying and control units, with the exception of the
microphone and phototube amplifiers, are designed for mounting on
a standard relay rack or for portable use with interconnecting cables
between the different units. Also, the controls are so located as to
facilitate this kind of operation. This is quite desirable because in
some applications it may be convenient to locate the mixer as well
as the complete amplifying and recording equipment in one room;
whereas, in other applications, it may be desirable to operate the
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
399
mixer and monitoring system remotely from the other amplifying
equipment; and operate this amplifying equipment, in turn, re-
motely from the recorder or re-recorder. A relatively small amount
of power is required to operate this equipment.
A high-quality film phonograph is provided. This unit is greatly
improved as to frequency characteristic and speed variation, and,
in addition, abrades the film considerably less.
Fig. 1 shows a photograph of an installation at the studios of
FIG. 1.
High fidelity film recording system installed at the Burton Holmes
Studio, Chicago, 111.
Burton Holmes Lectures, Inc., at Chicago, 111. From left to right
are shown a 35-mm. recorder, amplifier and control rack, phototube
amplifier, and a 35- to 16-mm. re-recorder (consisting of a 35-mm.
film phonograph and a 16-mm. recorder mounted on the same base
and mechanically connected).
Fig. 2 shows a diagram of the new recording equipment. Four
microphones, type 44- A, are connected to their respective micro-
phone amplifiers, type PA-82. The impedance of each line between
400
SIDNEY READ, JR.
[J. S. M. P. E.
the microphone and the microphone amplifier is 250 ohms. One or
more of the microphones and microphone amplifiers may be replaced
by phototubes and phototube amplifiers, type PA-79, when it is de-
sired to re-record. The phototube is located in the film phonograph,
and is connected to the phototube amplifier by a 50,000-ohm line.
This line is about two and one-half feet long, and consists of a low-
capacity cable well shielded against external fields. The lines be-
tween the outputs of the microphone and phototube amplifiers and
the input of the microphone mixing panel have an impedance of
VELOCITY MICROPHONES (<W-A)
OR
PHOTOTUBES
MICROPHONE AMPLIFIER5(PA-62)
OR
PHOTOTU&E AMPLIFIER.5(PA-79)
r
"A"POWI
ONLY.
:R s
UPPLY
POWER
SUPPLY
90VD.C.
1
POWER
SUPPLY
GROUND
REOOCT
•WISE
ON
ER
)
.'*'"
YD*.
AMPLIF
.RECORD
AMPLIF
(PA-1
ING
ER
5)
RECORDER
(P
M8)OR
PR-19)
RECORDER
MONITORING
SPEAKER
(PL-5Z)
FIG. 2. Sound recording equipment; diagram of
components and interconnecting cables.
250 ohms. These outputs are combined in a microphone mixer,
type PB-37, in which it is possible to adjust independently the
volume output of each microphone or phototube amplifier, as well
as that of the combined output. The microphone distribution
panel, type PB-12, serves as a junction box for connecting the outputs
of the microphone and phototube amplifiers to the inputs of the
microphone mixer and for furnishing the d-c. power for those units.
The output of the microphone mixer is fed through a 500-ohm line
into the compensator panel, type PB-70. This unit accentuates
May, 1933] RCA VICTOR RECORDING EQUIPMENT 401
the high frequencies so as to correct for the processing losses at those
frequencies. The output of the compensator panel is connected to
the input of the type PA -7 5 recording amplifier through a 500-ohm
line. This amplifier raises the audio voltage to a sufficiently high
level to operate the recording galvanometers. The connection is
made by means of a 500-ohm line. A small part of the energy fed
to the recorder is utilized in operating the ground noise reduction
amplifier, type PA -71. This amplifier rectifies and filters the audio
voltage and furnishes a biasing current for the auxiliary or bias
winding of the recording galvanometer. The input of the monitoring
amplifier, type PA-76, is connected in parallel with the output of
the recording amplifier, the connection being made through terminals
on the decompensator, which is physically a part of the type PB-70
compensator panel. The monitoring amplifier has a high-impedance
input, thus requiring a negligible amount of audio power from the
recording amplifier. The decompensator provides sufficient high-
frequency attenuation to correct for the increase of voltage with
frequency, caused by inserting a portion of the compensator into
the input of the recording amplifier, as well as that resulting from
the increase of galvanometer impedance with frequency.
Fig. 2 also shows the power connections to the various units.
The power for the filaments in the microphone distribution panel is
obtained from an 8- volt storage battery, requiring 2.5 amperes when
four microphone or phototube amplifiers are used. The plate
voltage is 180, supplied by medium duty "B" batteries delivering
28 milliamperes when four microphone amplifiers are used and 14
milliamperes when four phototube amplifiers are used. The same
"A" supply may be used in common for this unit, the booster ampli-
fier (single stage of amplification in the type PB-70 compensator
panel), the recording amplifier, and the ground noise reduction
amplifier. However, it is usually desirable that the "B" voltage
for this unit be obtained from a separate battery. The filament
current for the booster amplifier of the compensator, the recording
amplifier, and the ground noise reduction amplifier is obtained from
a common 8-volt storage battery. These units require a total cur-
rent of 6 amperes. The plate voltage for the booster amplifier of
the compensator and the recording amplifier, 180 volts, is obtained
from heavy duty dry "B" batteries. The total current is 60 milli-
amperes. The plate voltage for the ground noise reduction amplifier,
90 volts, is obtained from heavy duty dry "B" batteries, delivering
402
SIDNEY READ, JR.
[J. S. M. P. E,
a total current of 45 milliamperes. The monitoring amplifier requires
a total power of 70 watts from a 1 10-volt, 50- to 60-cycle source. The
field of the monitoring loud speaker is excited by the monitoring
amplifier. The power for the fields and exciter lamps of the re-
corders and film phonographs is supplied by a storage battery. An
8-volt battery is sufficient except when a film phonograph is used,
in which case a 12-volt battery is required. The total current for
each recorder is 7.6 amperes, while that for a film phonograph is
6.6 amperes. The power for driving the motors of the recorders
and film phonographs is obtained from a 3-phase a-c. source or from
a master selsyn generator. These units may be obtained for either
50- or 60-cycle as well as for selsyn operation.
FIG. 3.
Sound recording equipment; frequency characteristic of
recorded amplitude.
A standard 35-mm. recording equipment, type PM-29, as shown
in Fig. 2, weighs approximately 500 pounds, including one 35-mm.
recorder, four velocity microphones, four microphone amplifiers,
four 1000-ft. film magazines, and all bias batteries. Fifty pounds
is the maximum weight of any unit, except the recorder, which weighs
approximately 185 pounds. The total weight of the recommended
plate supply batteries is approximately 125 pounds. If the amplify-
ing equipment is mounted on a standard rack, type 9-D, the weight
of the equipment will be increased approximately 75 pounds.
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
403
Fig. 3 shows the over-all frequency characteristic, measured from
the input of one of the fhixers to the recorded amplitude on the film,
for both 35- and 16-mm. recording or re-recording. The increase
of response at the high frequencies counteracts the film loss so as
to make the output from a print of the recorded film essentially
constant. Of course, in order to obtain such a result, it is necessary
that the sound reproducing equipment have an over-all frequency
characteristic that is flat considering the width of the slit and the
gas amplification of the phototube.
Fig. 4 shows the measured characteristic of a 35-mm. print made
from a 35-mm. negative, which, in turn, was recorded on a pro-
duction recording equipment, maintaining constant the input voltage
to one of the inputs of the microphone mixer. Since the frequency
characteristic of the ribbon microphone and its amplifier and that
FIG. 4. Sound recording equipment; frequency characteristic of 35-mm.
recorded film after printing.
of the phototube amplifier including the film phonograph slit loss
are essentially flat, as will be shown later, it is easily seen from this
curve how faithfully the output from prints of recorded and re-
recorded films will approach the sound input to the microphone and
the output from the film played in the film phonograph. This
output is a faithful reproduction, within plus or minus 2 decibels,
of the original sound for frequencies between 50 and 9000 cycles
per second.
RECORDERS, RE-RECORDERS, AND FILM PHONOGRAPHS
The following units are available and may be used with the same
type of amplifying equipment: (1) type PR-18, 35-mm. recorder;
(2) type PR-19, 16-mm. recorder; (3) type PB-36, 35-mm. film
phonograph; (4) type PB-38, 35- to 16-mm. re-recorder.
404
SIDNEY READ, JR.
[J. S. M. P. E.
Since a paper2 giving a detailed description of these units has
already been published, only the parts involved in the audio circuits
will be considered.
Fig. 5 is a schematic diagram of the audio and power circuits of
a 35-mm. recorder. From this diagram, it may be seen that the
audio signal, on entering the recorder, passes into an impedance of
500 ohms and is stepped down to match the 2-ohm modulation
coil of the galvanometer. The drop in voltage across the 25-ohm
resistor, in series with the 500-ohm side of the transformer, furnishes
the necessary voltage for operating the* ground noise reduction
amplifier. The auxiliary, or bias winding of the galvanometer,
-»-JQ TYPE PA-75
RECORDING
f -.-AMPLIFIER
J!tTO TYPE PA- 11
*_-[_».e<NR. AMPLIFIER
*«SM
T0 3Mf- fc° rd-
- 220 VOLT
--»• SUPPLY
FIG. 5. Schematic diagram of model 4PR18A1 35-mm. film recorder.
receives the proper amount of direct current to reduce the clear
portion of sound track when no audio signal is applied, and to increase
the clear portion sufficiently so as to prevent overshooting when
modulation occurs. A more detailed description of this action will
be given when describing the ground noise reduction amplifier.
A switch in the audio circuit of the recorder provides for disconnect-
ing the audio output of the recording amplifier from the modulation
winding and also from the input of the ground noise reduction ampli-
fier to allow for monitoring without the galvanometer in the circuit
and for protecting the galvanometer when not in use. The galvanome-
May, 1933 ] RCA VICTOR RECORDING EQUIPMENT 405
ter furnished with this unit is of the electromagnetic type, and is
more sensitive than the string or oscillograph type of unit, making
it possible to use a larger mirror. The increased size of mirror
reduces the stray light and allows a greater depth of focus of the slit
on the film, thereby resulting in a greater response at the high fre-
quencies. The deflection of this unit is substantially constant for
all frequencies below the resonant frequency, which is 9000 cycles.
The damping is such as to limit the deflection at resonance to about
three decibels above the deflection at 1000 cycles.
The audio and power circuits of the 16-mm. recorder are identical
to those of the 35-mm. unit, except in that a low-pass filter is in-
serted in the 500-ohm input circuit in order to suppress all frequencies
greater than 4000 cycles. The reproduction, from 16-mm. film,
of frequencies greater than that results in considerable distortion
and very little useful output, because of the reduced speed of the
film, thirty-six feet per minute.
The 35-mm. film phonograph is somewhat similar to the 35-mm.
recorder. The recording optical system is replaced by a reproducing
optical system, and the phototube is so mounted that light from the
optical system passes through the sound track and thence to the
light-sensitive element.
The 35- to 16-mm. re-recorder consists of a 35-mm. film phonograph
and a 16-mm. recorder mounted on the same base and mechanically
connected. This arrangement provides a simple means for re-
recording from 35- to 16-mm. film without the usual selsyn installa-
tion.
VELOCITY MICROPHONE, TYPE 44-A
The velocity microphone3 provides for:
(1) A transformation of sound into electrical energy that is practically uni-
form at frequencies from 70 to 10,000 cycles per second.
(2) A permanent magnet type of field.
(3) A uniform directional characteristic for all frequencies.
(4) Remote operation as regards the microphone amplifier.
(5) An open circuit voltage output of 90 microvolts per dyne per sq. cm.,
referred to an output impedance of 250 ohms.
(6) Cushion and suspension mounting, with provision for rotation about both
vertical and horizontal axes.
(7) Protection against disturbances due to wind.
Fig. 6 shows two views of the 44-A velocity microphone, with and
406
SIDNEY READ, JR.
[J. S. M. P. E.
without a wind screen. This wind screen can be easily attached to
or removed from the microphone ; it is not required for studio work,
because suitable protection against wind disturbance which would
2 CONDUCTOR
SHIELDED CA&LE
(RUft&ER COVERFO)
3 CONDUCTOR
CONNECTOR
FIG.
The velocity microphone (44- A) showing suspension mounting and
wind screen.
CLAMPING SCREW5 FOR
HORIZONTAL SWIVEL
R1&50N X
CLAMPS
'SNNER COVER SCREEN
FIG. 7. Velocity microphone (44- A} with ou
screen removed.
half of inner cover
be encountered in this kind of work, as well as protection against
damaging the ribbon, is provided by two cover screens.
Fig. 7 is a view of the microphone with the outer and one-half
May, 1933] RCA VICTOR RECORDING EQUIPMENT 407
the inner cover screen removed. Fundamentally, this microphone
consists of a thin aluminum ribbon suspended in a magnetic field
produced by permanent magnets. The sound waves cause this
ribbon to vibrate in the magnetic field, thereby producing a voltage
drop between the ends of the ribbon. A transformer is used for
stepping up this voltage sufficiently to operate into the 250-ohm
input of the microphone amplifier.
One advantage of the velocity microphone is its ability to operate
uniformly, independently of changes in climatic conditions, such as
atmospheric pressure, humidity, and temperature, any or all of which
considerably affect other microphones.
Another important advantage of the velocity microphone is its
directional property. Since the ribbon is suspended in free space,
sound waves approaching the microphone in the plane of the ribbon
have no effect upon it. Sound waves impinging on either side of the
ribbon and perpendicularly incident to the plane of the ribbon have
a maximum effect. For equal distances from the transmitter, sound
waves incident at an angle of 70 or 80 degrees from the normal to
the ribbon will have practically no effect ; whereas, for those incident
at an angle of 45 degrees from the perpendicular, the sensitivity is
approximately 70 per cent of the maximum, and the quality is un-
changed. The response of this microphone to sounds originating
in random directions is one-third that of a non-directional micro-
phone. For the same allowable recorded reverberation, the velocity
microphone can be used at a distance 1.7 times the distance at which
a non-directional microphone can be used. It is at once apparent
that this characteristic is of great value in overcoming some of the
difficulties encountered in reverberant sets by reducing the response
to undesired reflected sounds, and in obtaining better balance and
selectivity in recording. Extraneous direct or reflected sounds
approaching the microphone from the side will have little or no
effect. The background noises and reflected sounds are therefore
reduced; an effect that increases, by comparison, the quality of
the direct sounds, and reduces the necessity of using highly sound-
proofed booths and "blimps," provided that advantage be taken of
the directional characteristic when placing the cameras. The
camera, for example, may be operated outside the booth if it be
placed in the "dead zone;" that is, in the plane of the ribbon of the
microphone, provided that none of the camera sound is returned
to the microphone from any other direction by reflecting surfaces.
408
SIDNEY READ, JR.
[J. S. M. P. E.
This condition may generally be realized in out-of-door recording,
and in the studio a considerable reduction in the amount of noise
picked up from the camera may be effected.
This type of microphone responds faithfully to all sound vibrations
over the range of frequencies from 70 to 10,000 cycles. Curve 1
of Fig. 8 represents the free-wave calibration of this microphone,
showing that the output at 10,000 cycles is only 3.5 decibels below
that at 1000 cycles. No "peaks" or "dips" occur in the character-
istic of this microphone that deviate from curve 2 by more than 1
decibel, which represents approximately the degree of dependence
that may be placed upon the acoustical measurements. This
is a matter of prime importance in choosing a microphone, as sharp
"peaks" or "dips" in the characteristic cause very objectionable
ijaMD .MaZDPHpNEJJMPUFlEH (forSE
FIG. 8. Sound recording equipment; frequency characteristic of velocity
microphone (44- A) and microphone amplifier (PA-82).
distortion, especially when a wide frequency range is covered. The
uniformity of the response is due principally to the smallness of the
size and mass of the velocity element placed in free space. Other
microphones are prevented from producing as faithful a response
by the size or mass of their diaphragms, or by the fact that the
diaphragms are required to work against more or less closed air
chambers. The faithfulness of response of this microphone imparts
a naturalness of tone and a distinctness of speech not hitherto attain-
able with other units.
The open circuit voltage of the microphone is 90 microvolts for a
sound input of 1 dyne per sq. cm. The output impedance of the
unit is 250 ohms. This sensitivity is approximately 2x/2 times that
of the condenser microphones generally used.
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
409
MICROPHONE AMPLIFIER, TYPE PA-82
The microphone amplifier provides for:
(1) Sufficient amplification (50 decibels) to increase the voltage output of
the velocity microphone to a suitable level for mixing.
(2) Slight accentuation of the high frequencies, so as to compensate for the
reduction that occurs at those frequencies in the velocity microphone; thereby
resulting in a uniform response up to 10,000 cycles.
(3) Negligible generation of noise.
Fig. 9 is a side view of the PA-82 microphone amplifier with the
cover removed and the radiotrons in position. As the photograph
CCA- 23fo
RAOIOTRON
CANNON
TYPE P
CONNECTION TO
MICROPHONE
/INPUT
'TRANSFORMER
CAPACITOR
PACK
CANNON TYPE F
CONNECTION TO
MICROPHONE
OtSTRlbUTiON
PANEL
OUTPUT
TRANSFORMER
RU&8ER OA3KET
FIG. 9. Microphone amplifier (PA -82}; cover removed.
shows, the radiotrons and amplifier assembly are mounted on
cushions on two studs, which later are mounted on the base and
act as a supporting structure for the case of the amplifier. The
projecting portion of the studs is threaded for thumb nuts, which
hold the cylindrical cover in place. Ears are provided on the cover
for suspending the unit. The input connection from the microphone
to the unit is made by a cannon type P receptacle, while the output
and power supply connections are made to the microphone dis-
tribution panel by means of a cannon type F plug. As shown by the
schematic diagram, Fig. 10, the microphone amplifier consists of an
410
SIDNEY READ, JR.
[J. S. M. P. E.
input transformer feeding an R.CA-236 radiotron resistance-coupled
to an RCA-237 radiotron which is, in turn, coupled to a 250-ohm
line by means of a step-down transformer. The bias voltage for
the first stage, including the screen grid, is obtained from a "bleeder,"
while the second stage is self -biased. The plate and screen grid
circuits are individually filtered so as to prevent disturbances from
the power supply from entering the audio circuit. By using radio-
trons of the heater type, such disturbances are avoided in the fila-
ment circuit. The bias resistor of the second stage is by-passed by
a small capacitor, which provides sufficient high-frequency com-
pensation to counteract the slight loss of high frequencies in the
microphone.
The combined frequency characteristic of the 44-a microphone
and the microphone amplifier is shown by curve 2 of Fig. 8, which
RCfl
0 OUTPUT
FIG. 10. Schematic diagram of microphone amplifier (PA-82).
does not deviate from a straight line by more than ±1 decibel,
from 150 to 10,000 cycles. The response decreases slightly from
150 to 70 cycles, the response at the latter frequency being 2.4
decibels below that at 1000 cycles.
The noise generated in the amplifier, due to "shot effect" in the
radiotrons and to other causes, has been reduced to a negligible
value; in fact, such noise represents only about 10 per cent of the
total noise that would be encountered due to the thermal agita-
tion, at room temperature, of a high-grade 250-ohm wire-wound
resistor connected across the input terminals. The plate supply
required for this amplifier is 180 volts at a current of 7 milliamperes.
The required filament supply is 8 volts at 0.6 amperes.
May, 1933] RCA VICTOR RECORDING EQUIPMENT
PHOTOTUBE AMPLIFIER, TYPE PA-79
411
The phototube amplifier provides for:
(1) Sufficient amplification (27 decibels) to increase the output voltage of the
phototube to a suitable level for mixing with the outputs of the microphone
amplifiers.
(2) Slight accentuation of the high frequencies, so as to compensate for the
insufficient response of the phototube at those frequencies, as well as for the losses
due to the width of the scanning slit.
Fig. 11 is a view of the PA-79 phototube amplifier, with the
housing removed and the radio trons in place. This amplifier is of
the same size as the microphone amplifier. The output and power
connections are made by means of a cannon type F plug, and the
RUBBER SUSPENSION
flNO BUFFER CUSHIONS
AMPLIFIER COVER
RADIOTRONS
RCA- Z37
TO PHOTOTU&E CIRCUIT OF
FILM PHQNOQRAPH,
TO MICROPHONE
DISTRIBUTION PANEL
FIG. 11. Phototube amplifier (PA -79}; cover removed.
same A and B voltages are required for this unit as for the micro-
phone amplifier. The input is obtained from a phototube mounted
in the film phonograph, as mentioned under the description of that
unit. The connection from the film phonograph is made by means
of a shielded cable 2.5 feet long, using cannon type P connectors.
Fig. 12 is a schematic diagram of the unit. The polarizing voltage
of the phototube is supplied through a resistance-capacity filter
and a 50,000-ohm load resistor. The impedance of the resistor is
small enough to prevent appreciable high-frequency losses when
412
SIDNEY READ, JR.
[J. S. M. P. E.
used with the connecting cable mentioned above. The load re-
sistor is capacity-coupled to the grid of the first RCA-237. The
output of this radiotron is, in turn, resistance-capacity-coupled to
a second RCA-237. To the output of the latter is connected a
transformer, which adjusts the impedance to match a 250-ohm line.
All plate circuits are filtered by resistance-capacity networks, so
as to prevent surges from the B supply from entering the audio
circuit. By using radiotrons of the heater type, such surges in
the audio circuit due to variations in the "A" supply are avoided.
Curve 1 of Fig. 13 is the frequency characteristic of this amplifier,
,5 RCA-257
yn
PHOTOTUbE
FIG. 12. Schematic diagram of phototube amplifier (PA-79\
FIG. 13. Sound recording equipment; frequency characteristic of photo-
tube and phototube amplifier (PA-79).
while curve 2 shows the combined characteristic of the phototube and
cable and the phototube amplifier. The combined characteristic is
flat within 1 decibel, from 40 to 10,000 cycles.
Since the output impedance, frequency characteristic, supply
voltages, and means of making connections are identical, this unit
may be used interchangeably or simultaneously with the microphone
amplifier. The plate current of the phototube and amplifier is 3.5
milliamperes, at a supply voltage of 180. The filament current is
0.6 ampere obtained from an 8- volt source.
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
413
AMPLIFIER AND CONTROL RACK
The remainder of the amplifier and control equipment is usually
mounted on a standard relay rack, as shown in Fig. 14. However,
any or all of these units may be operated remotely from each other.
All the units are portable, as well as suitable for operation on racks.
MICROPHONE DISTRIBUTION PANEL, PB-12
The microphone distribution panel provides for:
(1) Control of the power supply to four microphone or phototube amplifiers
with suitable protection for the A and B sources.
(2) Separation of the audio and power circuits of the four microphone or
phototube amplifiers, and connection of their audio circuits to the microphone
mixing panel.
"^vs^r"
GROUND NOISE REOUCT
AMPLIFIER PANEL
TYPE PA-71
MONITORING
AMPLIFIER PAN
TYPE. PA-76
MICROPHONE
DISTRIBUTION PANEL
MICROPHONE AND
PHOTOTUBE AMPllFIEf
MIXING CONTROLS
MONITOR
DE-COMPENSATOR SWITCH
MASTER VOLUME CONTROL
INTERMEDIATE
OLUME CONTROL
EST METER
ADPHONE MONITOR JACKS
BATTERY SWITCH
IMER OSCILLATOR SWITCH
TEST JACKS
BIAS CURRENT
MILLI AMMETER.
BATTERY SWITCH
ST JACKS
AS CURRENT CONTROL
AC LINE SWITCH
SENSITIVITY CONTROL
TERY SUPPLY CONNECTOR
BATTERY SWITCH
4IXING PANEl
TYPE P8-37
GROUND NOISE REDUCTION
MONITORING
VIPUFIER. PANEL
TYPE PA -76
MICROPHONE
DISTRIBUTION PA
TYPE PB 12
FIG. 14. (a) Front view of recording rack equipment; compartment
covers in place; (b) rear view of recording rack equipment.
The microphone distribution panel is suitably constructed to be
mounted either on a standard relay rack or on the wall. Fig. 15
is a front view of this unit. The front panel contains, in order from
left to right, a standard cannon type F eight-conductor plug, through
which the microphone sound current output is fed to the microphone
mixing panel and thence through the compensator panel to the main
recording amplifier; a fuse box; a power switch for turning the
filament and plate power on and off; and another standard cannon
type F male receptacle through which the filament and plate power
414
SIDNEY READ, JR.
[J. S. M. P. E.
supply for the microphones is connected to the power plug. This
latter connector may be placed on the rear of the panel if desired.
The fuse box contains the signal lamp and two fuses; a 6-ampere
fuse for the signal lamp and microphone filament circuits; and an
0.5-ampere fuse for the microphone plate circuits. The front cover
of the box is hinged, so as to permit rapid inspection and replacement
of fuses when necessary. A red bezel in the fuse box cover is located
in front of the signal lamp.
REAR SURFACE). OUTPUT AND
POWER 5UPPLY OF MICROPHONE
OR PHOTOTUBE AMPLIFIERS
POWER INPUT
RECEPTACLE.
SOUND OUTPUT
RECEPTACLE TO
MIXING PANEL
FIG. 15. Microphone distribution panel (PB-12).
MICROPHONE MIXING PANEL, PB-37
The microphone mixing panel provides for:
(1) Control of the individual audio outputs of four microphone or phototube
amplifiers, having an output impedance of 250 ohms.
(2) Control of the combined output of the four amplifiers.
(3) A uniform frequency response, from 30 to 10,000 cycles.
(4) Control of the frequency characteristic of recorded speech so as to prevent
a change in quality when amplified in the theater.
Referring to Fig. 16, the audio inputs to the microphone mixing
panel are connected through terminals to the respective attenuators
or volume controls. These attenuators are of the bridged T type,
which make it possible to maintain the impedance constant by
using only two movable contact arms instead of three, as in the
conventional T type of attenuator. The reduction in the number
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
415
of moving contacts contributes largely to the smoothness, silence,
and the dependability of these controls. The series resistors, R-6,
R-7, R-8, and R-9, in combination with the attenuator pads and the
coupling transformer, T-l, provide a constant impedance for the out-
puts of the four microphone or phototube amplifiers, as well as a con-
stant impedance at the output terminals of the microphone mixer.
Of course, if one or more microphones are disconnected from the input
terminals of the mixer, it is necessary to turn the attenuator controls
to zero in order to preserve the constant impedance relation. The
FIG. 16. Schematic diagram of microphone mixing panel (PB-37).
loss of power in the microphone mixer is only 8.5 decibels when all
the controls are in the position of maximum volume.
In the output circuit of the coupling transformer are connected
a volume control for controlling the over-all volume output of the
mixing panel, and a compensator and three-position key-switch for
introducing attenuation at both the low and the extremely high
frequencies. Attenuation is required at such frequencies when
speech is recorded at a normal level and then reproduced at a higher
level, as is usually the case in sound motion picture theaters. This
compensation corrects for the change in frequency response of the
human ear with an increase in sound intensity; thereby making it
possible to amplify the recorded speech to the desired level without
changing its quality. It may be of interest to note that the com-
416
SIDNEY READ, JR.
[J. S. M. P. E.
pensated volume control as used on radio receivers and phonographs
has the opposite effect, at low frequencies, from that of the speech
compensator; however, no attenuation of the extremely high
frequencies is attempted, since the upper response frequency of
most radio receivers is 4000 or 5000 cycles, in which range the char-
acteristic of the ear does not change greatly. The recording speech
compensator provides for good quality of reproduction of speech
at intensities greater than the original, as contrasted to the compen-
sated volume control of radio receivers, which provides for repro-
ducing music at abnormally low levels without changing its quality.
Fig. 17 shows the frequency characteristics of the microphone
mixer for the three positions of the speech compensator switch.
With this switch in the center position, no compensation is provided,
30 100 1000 10.00O
FIG. 17. Frequency characteristic of microphone mixer (PB-37}.
and the response is uniform within plus or minus 0.3 decibel, at all
frequencies from 30 to 10,000 cycles. An attenuation of 5 decibels
at 100 and 8000 cycles is produced when the switch is in the upper
position, and of 9 decibels at 100 cycles and 5 decibels at 8000 cycles
in the lower position. The characteristic obtained with the switch
in the lower position is suitable for recording conversational speech
or dialog, while that with the switch in the upper position is
adapted for recording lectures. The amplification system was so
adjusted that the reproduced output was equal in volume to that
of the original speech. The amplification of the system was then
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
417
increased, and its frequency characteristic so adjusted as to pre-
vent an apparent change in quality due to amplifying the original
speech. The results were then checked by actually recording and
reproducing speech in the theater. Under actual operation it was
found that one characteristic at the high-frequency end of the spec-
trum was satisfactory, whereas two different characteristics were
required at the low-frequency end. The average of these char-
acteristics agrees quite closely with the calculated value, as deter-
MICROPHONE OR PH0T0TU&E
AMPLIFIER MIXING CONTROLS
OUTPUT TERMINAL
&OARC>
INPUT
&OARP
FIG. 18. Microphone mixing panel (PB-37).
mined from Dr. Fletcher's4 contours of equal loudness for pure
tones, assuming a change in loudness from 50 to 70 decibels.
Fig. 18 is a front view of the unit. The mechanical construction
is of very high quality throughout, and it is assembled in such a
manner as to facilitate the installation and operation of the unit.
The front panel, which bears the four mixing controls, the over-all
volume control, and the speech compensator switch, is of such a
size and its mounting holes are so spaced that it may be easily
mounted upon a standard relay rack. The input terminal board is
located at the left of the unit, and the output terminal board is at
the right. The entire unit is completely shielded electrically by a
sheet metal enclosure. The rack adapters may be removed for
making the unit portable.
418
SIDNEY READ, JR.
COMPENSATOR PANEL, TYPE PB-70
[J. S. M. P. E.
The compensator panel provides for:
(1) Accentuation of the recorded amplitude of the high frequencies so as to
compensate for the recording and processing losses of either 35- or 16-mm. film.
(2) Sufficient amplification to overcome the inherent loss due to the com-
pensator circuit.
(3) Sufficient compensation of the monitoring amplifier so that the monitoring
loud speaker faithfully reproduces the original sound.
The compensator panel really consists of three individual units,
each having its own control switch; namely, (1) a compensator, for
counterbalancing the recording and film processing losses at the high
frequencies; (2) a booster amplifier, for counterbalancing the loss
due to the compensator; and (3) a decompensator, for counteracting
FIG. 19. Schematic diagram of compensator panel (PB-70}.
the effect of the compensator, as regards the input to the monitoring
amplifier, as well as the loss at high frequencies in the monitoring
loud speaker. The first two units are inserted in the line between
the microphone mixer and the input of the recording amplifier,
while the last unit is inserted in the input line to the monitoring
amplifier. The first two units are suitably shielded from the de-
compensator to prevent coupling between the input and output
circuits of the recording amplifier. Referring to the schematic
diagram of Fig. 19, the recording compensator is shown on the left,
the booster amplifier in the center, and the decompensator on the
right.
The compensator will be considered first. The output of the
May, 1933] RCA VICTOR RECORDING EQUIPMENT 419
microphone mixer and the input of the recording amplifier are con-
nected to the terminals so designated. The switch at the left pro-
vides for inserting either the 35-mm. compensator unit, XT-745,
or the 16-mm. unit, XT-746, or for direct connection. The com-
pensator units consist of two similar series resonance circuits, each
shunted by a resistor. One of the resonant circuits is inserted in
each side of the line, so as to provide electrostatic balance, and a
resistor is shunted across the input circuit. The action of the com-
pensator units is such as to accentuate the recorded amplitude of
the high frequencies, up to 9000 cycles and 4000 cycles, on 35- and
16-mm. film, respectively, so that the compensator has an effect
equal and opposite to that of the film losses. This results in true
and faithful reproduction throughout the frequency ranges of 50 to
9000 cycles and 50 to 4000 cycles, from prints of 35- and 16-mm.
recordings, respectively.
The booster amplifier will be considered next. The switch, shown
in the center of Fig. 19, provides for inserting the booster amplifier in
the audio circuit, ahead of the compensator units when they are in
the circuit, and for controlling the A and B voltages of the radio-
tron. When this switch is turned off, the amplifier battery is off,
and the amplifier stage is disconnected from the recording channel.
When this switch is set at its center position, the amplifier battery
power is turned on, but the amplifier circuits are still disconnected
from the recording channel. When the switch is turned on, the
amplifier is connected to the recording channel, and provides suffi-
cient amplification to overcome the losses of the compensator unit.
The booster amplifier is a single-stage unit, employing an RCA-£?7
radiotron and having input and output impedances of 500 ohms.
One half of the loading of the input transformer is across the primary
and the other half across the secondary, so as to obtain an improved
frequency characteristic. A step-down transformer provides for
coupling the plate of the radiotron to the 500-ohm input of the
recording amplifier. A reactor and coupling capacitor are used to
prevent the d-c. plate current from saturating the output transformer.
This amplifier has a gain of 15 decibels, and a frequency response
that is uniform within ± l/2 decibel for all frequencies between 30 and
10,000 cycles. Such a curve is shown in Fig. 20. The plate circuit
of the radiotron is adequately filtered, and the heater type of fila-
ment provides sufficient isolation of the cathode circuit from the
A supply. The plate circuit requires a voltage of 180 volts and a
420
SIDNEY READ, JR.
[J. S. M. P. E.
current of 2.5 milliamperes, and the heater and indicating lamp a
voltage of 6-8 volts and a current of 0.5 ampere.
The decompensator will now be considered. Due to the com-
pensation (as described above) of the audio-frequency currents from
the microphone mixer to the recording galvanometer, and to the
increase of the impedance of the recording galvanometer with fre-
quency, the sound from the monitoring loud speaker would be ob-
jectionably high pitched if the monitoring amplifier were bridged
directly across the input of the recorder. The switch shown at the
right side of Fig. 19 provides for inserting a reactor in series with
the monitoring amplifier when recording 16-mm. film, and for in-
serting part of the latter reactor (in shunt with a resistance), in
series with the input circuit of this amplifier when recording 35-mm.
film. This decompensation causes the sound output of the monitor-
FIG. 20. Sound recording equipment; frequency characteristic of booster
amplifier of compensator panel (PB-70).
ing amplifier to be a faithful reproduction of the original sound up to
frequencies of 4000 and 7000 cycles for 16- and 35-mm. operation,
respectively. The output for a frequency of 9000 cycles, in the
latter case, is approximately 5 decibels below that for 1000 cycles.
Fig. 21 shows a front view of the compensator panel, type PB-70.
RECORDING AMPLIFIER, PA-75
The recording amplifier provides for:
(1) Amplification of 80 db., with 66-db. control in 2-db. steps.
(2) Sufficient undistorted power output for the operation of two recorders.
(3) A frequency response of =*= l/2 db. from 30 to 10,000 cycles.
(4) Self- or battery-biased operation.
(5) Head-phone monitoring with volume control.
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
421
(6) Self-contained 1000-cycle microphone hummer for checking and ad-
justing the recording galvanometer and ground noise reduction system.
(7) Metering of filament, plate, and bias circuits.
The recording amplifier is a compact, ruggedly constructed unit
for amplifying the output signal from the microphone mixing panel
(type PB-37) sufficiently, and for furnishing ample power to operate
one or two 35-mm. or 16-mm. recorders. Its circuits incorporate
four stages of amplification, three voltage and one push-pull power,
utilizing a combination of resistance and transforming coupling.
PILOT
RADtOTBON
KECORDER,
COMPENSATION
SWITCH
MONITOR.
DECQMPENSATOR
SWITCH
FIG. 21. Compensator panel (PB-70).
The following radiotrons are used: two RCA-237's, one RCA.-236,
and two UX-171-A's. The amplifier is very carefully shielded,
and its power circuits are adequately filtered to prevent extraneous
noises from entering the audio circuits. The microphonic dis-
turbances have been greatly reduced by using ruggedly constructed
and adequately cushioned radiotrons. High-grade wire-wound
resistors are used in all circuits so as to insure against noises due to
defective resistors. Noises generated electrically in the amplifier
422
SIDNEY READ, JR.
[J. S. M. P. E.
circuits due to "shot" effect, or other causes, have been reduced to
negligible magnitudes. This amplifier has a gain of 80 db., and a
maximum undistorted power output of 800 milliwatts. The input
impedance is 500 ohms; the output impedances are 500, 250, and
167 ohms, providing for the parallel operation of one, two, or three
500-ohm loads. As may be seen in Fig. 22, the frequency response
of this unit does not vary more than ± J/2 db. over the frequency
range 30 to 10,000 cycles. Even at 16,000-cycles, the response is ap-
proximately 1 db. below the 1000-cycle response.
Two volume controls are provided: the master control across the
secondary of the input transformer having nineteen steps of 2 db.
each, and an off position; the intermediate, or interstage, volume
control having three steps of 14 db. each. The combined operation
10,000
FIG. 22. Sound recording equipment; frequency characteristic of recording
amplifier (PA-75).
of the two controls furnishes a range of volume of 66 db., in steps
of 2 db. Also, a volume control is provided for adjusting the audio
level for applications in which headphones are used for monitoring.
For adjusting the ground noise reduction amplifier, which will
be described later, a microphone hummer (oscillator) is mounted in
the recording amplifier. This hummer is used as a source of con-
stant frequency (approximately 1000 cycles), and is connected
ahead of the master volume control by means of a rotary switch.
Both volume controls may then be used in the usual way, for adjust-
ing the amount of 1000-cycle power furnished by the amplifier to
the recording galvanometer. The switch may be closed by in-
serting a coin or a screw driver in the slotted switch-shaft and rotat-
ing this shaft; this prevents the possibility of accidentally turning
on the oscillator switch while recording.
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
423
SADIOTRONS
UX-171A
MASTtR VOLUME
CONTROL
INTERMEDIATE:
VOLUME. CONTROL
MONITOR
VOLUME
CONTROL
POWER 5W1TCH
MICROPHONE
HUMMER
5WITCH
PATCHING
CORD
FIG. 23. Front view of recording amplifier (PA-75), showing interior of
radiotron compartment.
'C"P>ATTERY
COM PART M ENT
INPUT
TRANSFORMER
INTER STAGE: --
TRANSFORMER
OUTPUT
TRANSFORMER
RECORDER^
(OUTPUT)
TERMINAL
&OARD
POWER
INPUT
TERMINAL
&OARO
&ATTERY CONNECTION
RECEPTACLE WITH
OUST COVER IN PLACE
GROUND
TERMINAL
FIG. 24. Rear view of recording amplifier (PA-75).
424
SIDNEY READ, JR.
[J. S. M. P. E.
The plate circuit requires a voltage of 180-225, and a current of
55 milliamperes, obtained from heavy-duty dry batteries. The
filament current is 1.5 amperes, to be obtained from a 6- to 8- volt
storage battery. No C battery is required for the first three stages
of amplification, and the push-pull output stage may or may not
require such a battery, depending upon the power supplies available.
If a C battery is used, either side of the filament battery may be
grounded, the required plate voltage being in that case 180 volts.
If the tubes are self-biased, a 225-volt plate supply is necessary.
Fuses of the link type are used in the power circuits.
Figs. 23 and 24 are front and rear views of the amplifier. The
HOTE9 FOB MMtM%>
SELF CIAS'. 5-<> NOT USED C, CONNECTOR QROUNDEj)
-'B'OISCONNECTEO FROM •/\-CIHCUIT.-8" VOLTftQE = 2
bATTERY MAS: i-»"»OJVOLTl WHEN'-A-
A»E CONNECTED. '6-VOLTAQE -
S-** <W VOLTS WMEN'-B'IS CONNEC
•«A' •"&• VOLTAGE *1OO VOLTS FRONT VIEW
NOTE FOR F1L. SUPPLY '-
(DOR 6 VOLTS DETERMINED 6Y POSITION OF S-l FUSE
FIG. 25. Schematic diagram of recording amplifier (PA-75).
short length of relay panel mounted on each end of the front pro-
vides for mounting the unit on a standard relay panel. When the
amplifier is to be used portably, these short lengths of panel may be
easily removed. All connections are made beneath the fabricated
base. Connecting wires to the panel are sufficiently long to allow
the panel to be hinged about the base of the tube compartment,
thus providing easy access to the wiring and the internal parts.
Referring to Fig. 25, R-l and R-2 represent the master and inter-
mediate volume controls, respectively. The screen grid radio tron,
RCA-236, is used in the second stage rather than in the first stage
so as to prevent a change in frequency characteristic when the posi-
May, 1933] RCA VICTOR RECORDING EQUIPMENT 425
tion of the contact arm of the intermediate volume control, R-2, is
changed. By placing this volume control in the plate circuit of
the RCA-237, such a change in the frequency characteristic is reduced,
because the impedance of this circuit is much lower than that of the
RCA-236. With the present arrangement, the frequency character-
istic at any position of the volume control deviates from that shown
in Fig. 22 by less than 1/2 db.
Resistors, R-15, R-19, R-32, and R-33, in conjunction with a high-
resistance voltmeter and open circuit jacks, provide for measuring
the voltages and currents. This meter is used also to measure the
currents and voltages of the ground noise reduction amplifier. The
meter shunt resistors, R-32 and R-33, are connected in the low side
of the output transformer primary so as to prevent feed-back or
high-frequency losses due to the metering circuit. Either a 6- or
8-volt A supply may be used by connecting fuse S-l between the
appropriate pairs of terminals. When the fuse is connected between
the upper terminals, an 8-volt supply is required; when between
the common and the lower terminals a 6- volt source is required.
The output stage obtains its bias voltage from the C battery,
S-4, or the voltage drop in the resistor, R-28, caused by the d-c.
plate current flowing in it. When a battery is to supply the bias,
the minus B terminal is connected to either the minus A or plus A
terminal, short-circuiting the bias resistor, R-2 8. When self -biased,
this connection is removed, the battery S-4 is disconnected, and the
circuit is closed ; a binding post is provided in the C battery box for
connecting these leads together. It is necessary to increase the
B voltage from 180 volts to 225 volts for self -biasing ; the voltage
amplifier stages operate satisfactorily with either value of voltage.
Resistors R-20 to R-2 5, inclusive, are inserted into the output
circuits so that the output radiotrons may be matched to the correct
impedance for delivering maximum undistorted power while main-
taining the output impedance of the amplifier equal to the load
impedance. Half the resistance is inserted into each side of the
line, so as to maintain a balanced output. The impedance of the
recorder at 1500 cycles is approximately 500 ohms, which is equal
to that of the amplifier output circuit, while at low frequencies the
recorder impedance decreases to about 70 per cent of this value.
If the series resistors were not used and the ratio of the output trans-
former were changed so as to match the recorder, as stated above,
the output radiotrons would be working into an impedance less
426 SIDNEY READ, JR. [j. s. M. P. E.
than their plate impedance; whereas the load impedance should
be about three times the plate impedance of these radiotrons for
maximum power output with a minimum of distortion. If the
load impedance were matched to the plate impedance, the same
amount of distortion would occur when delivering an output power
of 500 milliwatts as now occurs when delivering 800 milliwatts.
Of course, making the impedances equal would allow a greater output
of power when distortion is not considered. Also, the present
method of matching results in a slight loss of amplification compared
with what would be obtained with equal impedance matching.
The oscillator (microphone hummer), T-4, obtains its exciting
current from the filament battery. Part of its 1000-cycle output
is applied across the input of the master volume control by means
of the potentiometer, R-35. Switch 5-5 controls the audio and
power circuits.
MONITORING AMPLIFIER, PA-76
The monitoring amplifier provides for:
(1) Complete a-c. operation.
(2) An amplification of 27 db. with a 40-db. control of volume.
(3) High impedance (bridging) input, so as to require negligible power from
a 500-ohm line.
(4) Sufficient undistorted power output (4 watts) for operating two monitoring
loud speakers.
(5) Field exciting current for one loud speaker.
(6) A frequency response of ± l/2 db. from 30 to 10,000 cycles.
A loud speaker placed in the recordist's booth enables him to
observe aurally the effect of manipulating the mixing controls, so
that the recording, when reproduced in the theater, will reflect ac-
curately the impressions, moods, and ideas that the director and
recordist desire to create. To serve properly such a purpose, the
monitoring loud speaker and amplifier must be of the highest quality.
The monitoring amplifier shown in Figs. 26 and 27 is a small,
compactly built, semi-portable unit, completely operable on any
110-120- volt, single phase, 50-60-cycle supply. About 70 watts of
power are required. This unit is designed to be connected to the
main recording amplifier output circuit through the decompensator
of the compensating panel, type PB-70, without requiring appre-
ciable audio power input, and to furnish sufficient undistorted power
for operating one or two monitoring loud speakers. Although the
May, 1933] RCA VICTOR RECORDING EQUIPMENT
427
RA010TRONS
FUSE:
POWER
SWITCH
FIG. 26. Front view of monitoring amplifier (PA -76}, showing interior of
radiotron compartment.
POWER
TRANSFORMER
105 -125 VOLT
50-foO CYCLE.
IN'PUT
INPUT TRANSFORMER
(NOT SHOWN)
.4NTERSTAGE
TRANSFORMER
TPUT
TRANSFORMER
LOUDSPEAKER
TERMINAL
&OARD
qROUNO
LOUDSPEAKER TERMiNAL
FIELD SUPPLY
RECEPTACLE
FIG. 27. Rear view of monitoring amplifier (PA-76).
428
SIDNEY READ, JR.
[J. S. M. P. E.
monitoring amplifier is operated on alternating current, the output
hum in the monitoring loud speaker is below the audible level at any
setting of the volume control. Fig. 28 shows that the response of
this amplifier does not vary more than =•= l/2 db. over the frequency
range 30 to 10,000 cycles. An output power of 4 watts may be
obtained without exceeding 5 per cent distortion.
The unit consists of a steel base on which are mounted the trans-
formers, reactors, capacitors, etc. On the front edge of the amplifier
base are mounted the volume control and the power switch. On the
back edge of the base are mounted the input terminal strip, output
terminal strip, and a two-conductor receptacle for the monitor loud
speaker field. A wall-type two-conductor plug for the 110-volt
power supply is mounted on the side of the base. On top of this
base and at the front edge is mounted a steel compartment containing
30 100 100O 10.000
FIG. 28. Sound recording equipment; frequency characteristic of monitor
amplifier (PA -76).
the tubes, fuse, and indicating lamp. A front cover is provided for
this compartment, removable by loosening two thumb screws, thus
providing easy access to the last-mentioned parts.
Referring to Fig. 29, the input transformer, T-l, loaded with the
100,000-ohm volume control, R-l, has an input impedance of 20,000
ohms, making possible the bridging of this amplifier across a 500-
ohm line without requiring appreciable power from that line. The
first audio stage utilizes an RCA-237 radiotron, resistance-capaci-
tance coupled to a push-pull transformer that furnishes audio voltage
to the grids of the UX-245 radiotrons. The first stage obtains its
bias voltage from the bleeder resistors, R-3 and R-6. Bias for the
UX-245 radiotrons is obtained from part of the voltage drop in the
speaker field, which is connected between the ground and the negative
side of the rectified plate voltage supply. The total plate current
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
429
plus the bleeder current is equal to 100 milliamperes, which is the
amount of current required for the 100-volt speaker field. By this
arrangement it is possible to obtain the plate and the bias voltages,
275 and minus 54, respectively, for the UX-245 radiotrons, as well
as the exciting current for the loud speaker field from a single UX-
280 rectifier. The output transformer has three secondary ter-
minals from which one 15-ohm speaker, or two in series, may receive
audio power when the appropriate pair of terminals is used. Either
a 110- or 120- volt source of power may be used by connecting the
fuse, S-2, between the appropriate pair of terminals. The fuse serves
as a tap-changing switch for the power transformer, T-4, which
furnishes the correct alternating filament voltages for the RCA-237,
UX-245, and UX-280 radiotrons, as well as the plate and field
FIG. 29. Schematic diagram of monitoring amplifier (PA-76).
supply, which is rectified by the UX-280 radiotron. Reactor L-l,
in combination with capacitors C-4 and C-5, forms a tuned filter
for the plate and grid circuits and for the loud speaker field. The
speaker field and the capacitor, C-3, provide additional filtering for
the plate and grid circuits of the first stage and for the plate circuit
of the power stage. A resistance-capacitance filter, composed of
resistors R-9 and R-10 and capacitor C-6, provides additional filtering
of the grid circuit of the power stage. Further filtering is provided
for the grid and plate circuits of the first stage by the resistance-
capacitance filters, R2-R3-C1 and R5-C2, respectively. By placing
the filtering reactor and the speaker field in the negative side of the
high-voltage circuit, the maximum voltage to ground from the
430 . SIDNEY READ, JR. [j. s. M. P. E.
speaker field circuit is 100 volts, while the maximum voltage to
ground from any part of the amplifier is 275 volts. These voltages
to ground are considerably less than they would be if the filtering
were accomplished in the positive side of the rectifier circuit. In
that case, the voltage from one side of the speaker field to ground
would have been 375 volts, and special precautions would have had
to be taken in insulating the wiring to the speaker field.
GROUND NOISE REDUCTION AMPLIFIER, TYPE PA-71
The ground noise reduction amplifier provides for:
(1) Sufficient biasing current through the auxiliary winding of the recording
galvanometer to reduce the clear portion of the sound print to a track 2 mils
(0.002 of an inch) wide when no sounds are being recorded, thus greatly reducing
the reproduced surface noises.
(2) Increasing the width of the clear portion of the sound track to provide
for recording the signal currents impressed on the modulation winding of the
recording galvanometer.
(3) Adequate filtering and timing to prevent the recording of reproducible
vibrations due to the biasing action.
Previously, two methods of reducing ground noise have been
employed in commercial variable width methods of recording. Both
systems were used in conjunction with a variable width sound track
that was a single-edged black silhouette of the sound wave. In the
first system, the center of the recorded wave was shifted toward one
edge of the sound track, resulting in a narrow transparent line at
this edge of the printed sound track when no signal was applied. In
the second system,5 the center line of the recorded wave was kept in
the center of the sound track, and a mechanical shutter was used for
reducing the amount of transparent area of the printed sound track,
resulting in a narrow transparent line at the center of the track when
no signal was applied. When the signal was applied, the shutter
was deflected sufficiently to clear the peaks of the light vibrations.
The new, or third, method of reducing ground noise is applicable
to a symmetrical or double-edged variable width sound track. Fig.
30 (a) is a positive print of a 35-mm. negative speech record, extend-
ing over one complete cycle of operation of the ground noise reducing
system. As shown in the illustration, the sound track consists of two
similar waves, or oscillograms, of the voice modulation, which are
symmetrical about the center of the sound track. The area of the
sound track between these waves is transparent, while the remainder
May, 1933] RCA VICTOR RECORDING EQUIPMENT
431
of the track is opaque. The distance between the center lines of the
waves increases and decreases as the amplitudes of the waves increase
and decrease. In other words, the average width of the transparent
portion of the sound track is decreased as the amplitudes of the
waves decrease, resulting in a reduction of the reproduced noise due
to dirt particles, scratches, etc., on the surface of the film. The
FIG. 30. Diagram showing nature
of sound track and mean positions of
triangular image of light or different
degrees of modulation.
greatest reduction occurs at small amplitudes of modulation, when
surface noises are most objectionable. At zero modulation, the
center lines are spaced 2 mils (0.002 inch) apart, thus producing a
2-mil transparent band at the center of an otherwise opaque sound
track. When the total of the amplitudes of the two waves is 80
432 SIDNEY READ, JR. [j. s. M. P. E.
per cent or more of the width of the sound track, the center lines of
the waves are 35 mils apart. The speed of variation of the distance
between the centers of the two sound waves, or the average trans-
parent portion of the sound track, is so controlled as to prevent the
introduction of audible disturbances into the reproduced sound. A
rapid separation of these center lines occurs when a signal is impressed,
while the closing takesplace relatively slowly after the signal wave
ceases.
This method of reducing ground noise has the same advantage over
the first system referred to as the second system does: namely, the
clear portion of the sound print is in the center of the sound track.
This prevents the loss or distortion of signals of small amplitude
when the film is played on a reproducer whose scanning beam is so
poorly adjusted that it does not completely scan the sound track,
either because of improper adjustment or because of excessive weav-
ing of the film. It is an improvement over the second system in
that the modulating and darkening of the sound track are performed
by a single moving element, the galvanometer, thus requiring no
relative adjustment between two moving parts. A narrower trans-
parent track may be used, and less extraneous modulation due to
mechanical vibration is encountered, since the moving element, the
galvanometer, is much stiffer than the shutter previously used. The
present system requires careful damping of only one unit, the gal-
vanometer; whereas the second system required very careful damp-
ing of both the galvanometer and the shutter or light-masking de-
vice. Damping of the latter was required, due to the fact that its
resonance frequency was sufficiently low that, without damping,
this unit could be shocked into resonance by changes in the biasing
current. Also, the new system provides for completely controlling
the required filtering and timing in the electrical circuit, rather than
partly in the mechanical and partly in the electrical circuit.
In Fig. 30, (b) shows diagramatically the method of obtaining this
type of sound track. A triangle of light is focused on a mechanical
slit, an image of the slit being focused on the film. The recording
galvanometer provides for moving this triangle of light at right angles
to the axis of the slit, causing a change of width of the exposed part of
the sound track. Two windings are provided on the galvanometer.
One of these is a modulation winding, which causes the triangle of
light to oscillate when electric waves are impressed. The other is
an auxiliary, or bias winding, which, in conjunction with the ground
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
433
noise reduction amplifier, provides for shifting the triangle of light
so as to maintain the minimum average width of clear sound track,
after printing, without allowing the triangle of light to uncover the
mechanical slit completely, when electric waves are impressed on the
modulation winding. The solid triangles shown in the diagram repre-
sent the position of the triangle of light when no modulation is ap-
plied to the recording system. The dotted triangle represents the
mean position of the triangle of light when its amplitude of vibration
is equal to, or greater than, 80 per cent of full modulation of the sound
track. For intermediate amplitudes of vibration, the mean positions
of the triangle of light will always be between these two positions.
The dotted triangle represents also the position of the triangle of
light when neither bias nor modulation is supplied to the auxiliary
>> Y j
,9U-— *
-A-i" *A$ 2' ,
Of 30
FIG. 31. Schematic diagram of ground noise reduction amplifier (PA-71).
or modulation windings, respectively. The initial biasing current
required to shift the triangle of light from the dotted to the solid
position, as shown in the diagram, as well as the variation of this
biasing current with the amplitude of the sound wave, is supplied by
the ground noise reduction amplifier.
Fig. 31 is a schematic diagram of the type PA-71 ground noise
reduction amplifier. Included in this unit are two stages of amplifica-
tion, utilizing RCA.-112A and RCA-171-A radiotrons in the first
and second stages, respectively. The second stage (RCA-171-A)
furnishes power to a UX-280 rectifier, and a timing circuit composed
of capacitors 8 and 28, and resistors 13 and 29. The timing circuit
controls the rate of change of the rectified voltage used to bias the
grids of the three HCA.-238 pentodes in parallel. The combined plate
434 SIDNEY READ, JR. [j. s. M. P. E.
current of these tubes is the biasing current used in the auxiliary
winding of the galvanometer. By using three tubes it is possible to
obtain sufficient biasing current, 27 milliamperes, from a 90-volt
supply. It is desirable that this voltage be low, so as to require a
minimum of insulation between the auxiliary winding and the ground,
since the space available for such insulation is small. Also, a re-
duction in this voltage reduces the number of batteries required,
as the plate supply for this amplifier is independent of that of the
other units. The pentodes have a plate impedance sufficiently
high so as not to impose an appreciable load on the modulation
winding of the galvanometer due to the transformer action between
the two windings of that unit. Otherwise, the change of plate
impedance accompanying a change of the biasing current would
cause modulation of the recorded signal.
Potentiometer 12, Fig. 31, is used for adjusting the d-c. bias of the
RCA-238 radiotrons, so as to control the position of the triangle of
light when no audio signal is supplied to the system. This "no
signal" position of the triangle of light changes only slightly after
it is once adjusted. Such changes are due to aging of the batteries
or of the radiotrons, after extended use; however, they are in such
a direction, decreasing the current, as to increase the width of the
clear portion of the sound print, resulting only in a slight increase in
the amount of ground noise reproduced. Even if the supply voltage
of this unit were reduced to zero, the most serious consequence would
be a normal recording without ground noise reduction. The audio
input signal to the ground noise reduction amplifier is obtained from
the drop of voltage in the 25-ohm resistor, which is in the 500-ohm
input circuit of the recorder, due to the modulating current flowing
in this circuit. This method of obtaining the input signal is used
because the amplitude of vibration of the mirror is very nearly di-
rectly proportional to the modulating current, whereas the voltage
across the modulation winding increases with frequency.
Potentiometer 9 controls the reduction of the biasing current and,
accordingly, the shift of the triangle of light in relation to its ampli-
tude of vibration. This control seldom requires adjustment. The
time required to shift the triangle of light after a signal has been
applied to the modulation winding, causing the triangle to vibrate,
is the time that is required for the capacitors 28 and 8 to charge
through the resistor 29 and the resistance of the rectifier. Trans-
former 5 has a step-down ratio such that the reflected plate im-
May, 1933]
RCA VICTOR RECORDING EQUIPMENT
435
pedance of the radiotron UX-171-A is negligible as compared with
that of the rectifier or of resistor 29. The ratio of the capacitance
of 8 to the resistance of the rectifier is such that 0.001 second is re-
quired to charge capacitor 8. Capacitor 28 requires 0.006 second to
charge through the resistor 29, the resistance of the rectifier being
negligible. The capacitance of 8 is large with respect to that of 28;
therefore, a signal of only 0.001 second's duration would completely
charge capacitor 28 in 0.006 second after such a signal was impressed.
In other words, capacitor 8 is completely charged in 0.001 second,
and then discharges into capacitor 28 through resistor 29, since the
ratio of the resistance 13 to the capacitance 8 results in a discharging
T£5T JACKS
FIG. 32. Ground noise reduction amplifier (PA -71}.
rate that is much slower than the charging rate of capacitor 28. The
time required to shift the triangle of light to the position of zero
modulation, after the modulation has ceased, is 0.11 second, which is
the total time required for capacitor 8 to discharge through resistors
13 and 29. The two-stage timing circuit thus provides for con-
trolling the filtering and the timing independently. The rate of
increase of the clear portion of the sound track is sufficiently low to
prevent audible disturbances such as "clicks" or "plops," and suffi-
ciently rapid to prevent audible distortion due to "over-shooting."
The rate of reduction of the transparent portion of the sound track
436 SIDNEY READ, JR.
after the signal has ceased is slow enough to prevent second harmonic
modulation and, at the same time, is sufficiently rapid to prevent an
audible change in the hiss-to-signal ratio.
Meter 15 measures the bias current, which is supplied to the auxil-
iary winding through terminals 20, Switch 26 is used to disconnect
the auxiliary winding and to connect an equivalent resistor 27 across
the output of the ground noise reduction amplifier to facilitate ad-
justments of the system. An oscillator is provided in the recording
amplifier, as mentioned under the description of that unit, and fur-
nishes a convenient source of 1000-cycle voltage for such adjustments.
The total voltage and current required are 6 or 8 volts and 3.8
amperes from the A supply, and 90 volts and 45 milliamperes from
the B supply. Fig. 32 is a front view of the above-described amplifier.
REFERENCES
1 DIMMICK, G. L., AND BELAR, H.: "Extension of the Frequency Range of
Film Recording and Reproduction," /. Soc. Mot. Pict. Eng., XIX (Nov., 1932),
No. 5, p. 401.
2 ZIMMERMAN, A. G.: "Film Recorders," /. Soc. Mot. Pict. Eng., XX (Mar.,
1933), No. 3, p. 211.
3 OLSON, H. F.: "The Ribbon Microphone," /. Soc. Mot. Pict. Eng., XVI
(June, 1931), No. 6, p. 695.
4 FLETCHER, HARVEY: "Speech and Hearing," D. Van Nostrand Pub. Co.,
New York, N. Y., 1929, p. 230.
5 KREUZER, BARTON: "Noise Reduction with Variable Area Recording,"
J. Soc. Mot. Pict. Eng., XVI (June, 1931), No. 6, p. 671.
6 KELLOGG, E. W. : "A New Recorder for Variable Area Recording," /. Soc.
Mot. Pict. Eng., XV (Nov., 1930), No. 5, p. 653.
7 BUTTON, W. P., AND READ, S.: "Some New RCA Photophone Studio Re-
cording Equipment," /. Soc. Mot. Pict. Eng., XVI (Mar., 1931), No. 3, p. 315.
A NEW PROCESS OF TELEVISION OUT OF DOORS*
A. T. STOYANOWSKY**
Summary. — The problems involved in the transmission of motion pictures by
television are, in general, less difficult to solve in certain respects than the problems in
the television transmission of living subjects or objects in studios and, above all, out
of doors. In the following article, a description is given of an interesting invention
that changes the problems of television out of doors into corresponding problems of
motion pictures by television.
The experiments recently carried out in the various television
laboratories of the Baird group have proved the possibility of trans-
mitting images with sufficiently sharp detail to permit the expecta-
tion in the very near future of actual television in all of its applica-
tions.
We know that from now on, thanks to the experiments carried out
upon the occasion of the Radio Exposition in Berlin by the Central
Administration of the P. T. T. of the Reich, with a station transmit-
ting on ultra-short waves (7 m., 15 kw.) and by means of motion
picture transmitters of the Fernseh A. G., that the transmission of
an image of 10,800 points (90 lines) with horizontal form 3X4 cms.,
25 images per second, is an accomplished fact, and offers no further
difficulties.
Although one may conceive of images of 19,200 points (120 lines),
for which very satisfactory local transmissions have been effected,
and even of 43,200 points (180 lines), it appears that practical tele-
vision ought to attain a fineness of scanning of 20,000 points. In
effect, the image obtained with this degree of detail is sufficiently
sharp to satisfy the most exacting demands. The result thus ob-
tained is comparable to the motion picture of today, if not in the
detail effectively reproduced, at least in the quality of the image
suggested.
The Fernseh A. G., which holds in Germany the rights of the Baird
* Translated from the original in La Technique Cinematographique, 4 (Jan.,
1933), p. 15.
** Director of Baird Natan Television.
437
438 A. T. STOYANOWSKY [j. s. M. P. E.
group, publicly demonstrated in April, 1932, sending and receiving
television apparatus using an image of 19,200 points.
The transmission was effected by means of a Nipkow disk 500 milli-
meters in diameter, with 120 hexagonal holes. The side of each hole
is 0.05 millimeter. These holes are pierced in small pieces of gold
foil supported by the disk. The sending was done with a motion
picture transmitting apparatus with a Zeiss Ikon projector. The
image projected on the disk was 9 X 12 millimeters. The transmit-
ting disk had a single spiral, and revolved at 25 revolutions per second.
The transmitting amplifiers comprised 8 stages.
The reception also took place on a Nipkow disk, by means of a
sodium vapor lamp. This disk, of dimensions essentially equal to
those of the sending disk, has a double spiral (Baird process).
By means of an optical system, the image was enlarged to about
7 X 10 centimeters. The brightness of this image is such that it
can easily be observed in a slightly darkened room.
TELEVISION TRANSMISSION OUT OF DOORS
An experiment was carried out by Baird Television, Ltd., upon the
occasion of the Epsom Derby, in the course of which a picture was
projected upon a screen several square meters in area in the Metro-
pole Theater in London.
The transmission was effected by the aid of three cables, each of
which carried an image of 2100 points at a rate of 12.5 images per
second ; but this complex system of transmission is somewhat limited
with respect to the detail of the transmitted image. For the transmis-
sion of moving scenes, an image of 9000 points appears to be a limit
that can not possibly be exceeded, even by the best technical means
and in very clear weather if not in sunlight. In cloudy weather, it
does not appear possible to effect the transmission of an image of
more than 3000 to 4000 points. The difficulties are partly optical
and partly due to the insufficient sensitivity of the cells.
To solve the problem, the Fernseh A. G. (licensee of Baird) has
launched out into an entirely new direction in which, after many at-
tempts and after surmounting many difficulties, they have attained
an altogether remarkable result by means of the transmission of
television with an intermediate film (Zwischenfilmsendung) . The
problem of scanning is, in effect, infinitely simpler for the transmission
of motion pictures. A film presents neither depth of field nor color,
and the most intense light may be used for illumination.
May, 1933]
TELEVISION OUT OF DOORS
439
TELEVISION TRANSMISSION BY FILM
A description of the apparatus as actually operated at the Radio
Exposition in Berlin follows:
Fig. 1 gives the general arrangement of the apparatus represented
in the photograph. The film used for taking the scene is contained
in the magazine, 1, and enters by a light-tight passage into a camera
of a current model. The exposed film passes by a covered passage
(with or without means of guiding) into a light-tight cabinet, 3, con-
taining the photographic solutions.
Once the film is developed and fixed, it passes into the television
scanning apparatus, 5. Then the film is rolled up on the drum, 6.
In Fig. 1, the film is indicated by 4. The variations of potential ef-
fected in a photoelectric cell by the variations of brightness are ampli-
fied in the usual manner by the amplifier, 8, and sent by the trans-
mitter, 9.
The possibility of the practical operation of the entire process
3
4
5
J
FIG. 1.
Diagram of the television transmitter employing an inter-
mediate film (Fernsehen, 1932, No. 3).
depends upon the minimum time necessary for the photographic proc-
essing. Assuming that 25 images per second are employed, and
that the height of each image is 18 millimeters (standard film), a rate
of motion of 0.45 meter per second is required for the film. If the
photographic processing requires, for example, 3 minutes, it is neces-
sary to pass into the cabinet, 3, 81 meters of film before getting any
results, which is a great disadvantage especially if the apparatus is to
be portable. Even the use of a film of reduced dimensions hardly
simplifies the problem.
From these considerations and to render the process practicable,
it follows that it is necessary to reduce considerably the time neces-
sary to develop and, above all, to fix the film. The attempts in this
direction have been made in close collaboration with the motion
picture section of the Zeiss Ikon A. G., Berlin-Zellendorf.
440 A. T. STOYANOWSKY [j. s. M. P. E.
By the use of a special developer, it has been possible to reduce the
time necessary for development to x/2 second. The reduction of the
time of fixation is a much more difficult matter, but it has been
possible to find, finally, a solution that requires no more than 24 to
30 seconds. Tests with incompletely fixed images were unsatis-
factory, as the presence of a non-uniform layer gives rise to stains and
spots.
After the manufacture of a special film which, moreover, is particu-
larly sensitive, it has finally 'been possible to obtain total fixation in
4 to 5 seconds. In addition, it is helpful to insert, between the de-
veloper and fixing bath, a special solution that adds no more than
V2 second to the total time. Also, after the fixing bath, a supple-
mentary bath or a short washing (x/2 second) is added.
In order to save time, this washing may be done after the scanning.
Thus, the entire purely photographic process can be carried out in the
astonishingly short time of 10 seconds. The negative thus obtained
is of perfect photographic quality and may be used for printing a
positive.
The water that remains on the film can be removed so uniformly
that the scanning can take place without special precautions. After
scanning, the still moist film is rolled without other precautions,
upon a drum that is preferably kept in water. Ultimately, the film
is washed and dried, and serves for the making of ordinary positives.
The process has also the advantage, therefore, of permitting the fur-
ther exploitation of a film that has served for the transmission of
television.
Contrary to the usual method for sending motion pictures by
television with a Maltese cross pull-down and spiral disks, in the ap-
paratus described the film moves continuously. This is a necessity
because (1) it is essential not to subject the still moist film to violent
stresses; and (2) it is necessary to avoid risk of spattering the thin
layer of water that covers the film, which spattering would involve
optical difficulties.
Moreover, there is thus avoided the loss of 15 per cent in the height
of the image due to the shutter necessitated by an intermittent move-
ment. In this case, the holes of the exploring disk are not arranged
in a spiral but in a circle.
The installation used at the Berlin Exposition operated with 90
lines, corresponding to 10,800 points. The diameter of the scanning
disk was 500 millimeters; the scanning holes are regular hexagons
May, 1933]
TELEVISION OUT OF DOORS
441
0.09 millimeter on a side. It goes without saying that, apart from
the great precision necessary in the construction of the disk, it is
equally necessary to attain a high degree of precision in the movement
of the film, which is effected in a perfectly uniform manner without
the appearance of any distortion in the image.
The electrical and optical parts of the apparatus are represented
diagrammatically in Fig. 2. The light source, 1, is an incandescent
lamp, the filament of which is projected by the lenses, 2, upon the
disk, 3.
The image of the filament is a straight line, whereas the path of the
opening in the disk is a very slightly curved arc of a circle ; but, since
the diameter of the hole is only 0.156 millimeter, a greatly enlarged
image of the filament may be formed, under the best conditions of
FIG. 2. Diagram of the electrooptical system of the sending
apparatus.
illumination, which uniformly covers the opening in the disk over its
entire course.
The incandescent lamp is lighted by continuous current (10.5
volts, 15 amperes), and consumes less than 160 watts, which is not
excessive in view of the extreme enlargement necessary. The image
of the scanning hole is projected by the objective, 4, upon the film, 5,
which moves continuously. If desired, it is possible to provide a
condenser between the cell, 6, and the pupil of light scanning the film.
The driving of the scanning disk and the movement of the film are
effected by means of two separate synchronous motors (1500 rpm.)
actuated by the same alternating current, and consequently per-
fectly synchronized. The movement of the film is continuous in the
entire apparatus, excepting in the camera, which is of the ordinary
type. However, the movement in the camera must be synchronized
with the continuous movement of the film.
442 A. T. STOYANOWSKY [j. s. M. P. E.
This is accomplished by means of a flexible shaft between the
camera and the motor driving the film for scanning. It is not neces-
sary to regulate the phase of the motor driving the film with respect
to the scanning, since the scanning is done with a disk with holes ar-
ranged in a circle. If, on the other hand, an intermittent movement
Fig. 3. The intermediate film transmitter shown in this
photograph permits taking any event with the motion pic-
ture camera, develops the exposed film, and transmits the
film by television with a detail of 10,800 image points at a
rate of 25 images per second. The image can be trans-
mitted 15 seconds after being photographed.
of the film is employed with a spiral disk, it is necessary to provide a
precise adjustment of phase.
In the developing and fixing baths, no sprockets are found, but
only guide rollers which are turned in synchronism with the scanning
motor. For the movement of the 5-meter length of film that is in
the various parts of the apparatus at a given instant, the guide rollers
suffice. The scanned film is rolled upon the drum by means of an
ordinary motor (non-synchronous) through a friction coupling.
May, 1933] TELEVISION OUT OF DOORS 443
If the film in the camera magazine is exhausted, the motor that
drives the camera is automatically stopped so that a new roll of film
may be spliced on before the entrance to the machine, thus avoiding
rethreading of the film through all the guides. Taking scenes in the
studio or out of doors is done with an ordinary camera under ordinary
conditions.
The amplification is effected in the usual manner with an amplifier
of 8 stages. The apparatus functions, in spite of its provisional con-
struction, in a continuous and certain manner, and permits trans-
mission, with 10,800 image points of anything that may be taken with
a camera, independently of the aperture of the taking lens.
The new transmitter appears at first sight to have one decided
disadvantage. Although it is immaterial if the television amateur
sees events transmitted with a delay of 10 seconds, this delay would
become intolerable if the sound were transmitted simultaneously.
But this disadvantage can be avoided very easily if the sound is
recorded on the same film as the image, developed at the same time,
and then transmitted at the time at which the television scanning
takes place. This intermediate recording of the sound can obviously
take place on a separate film or by any other known process of re-
cording.
The described apparatus can be improved in a number of ways.
It should not be difficult, for example, to send a picture of 20,000
image points. It is equally possible to reduce further the time inter-
val between the taking of the scene and the reproduction by reducing
the time necessary for the photographic manipulations. The ap-
paratus could be mounted in such a manner as to be easily portable if
this should prove useful. The connection between a movable tele-
vision truck and the principal radio sending station could be effected
by means of an ultra-short wave transmitter in order to be directional,
if cables or ordinary overhead wires can not be considered, thereby
giving a broader band of transmission frequencies.
For the practical operation of this process, we shall meanwhile
await the solution of another technical problem, namely, the trans-
mission and reception of radiovision broadcasting on ultra-short
waves. The Baird group is actively studying this question and the
results already obtained are very encouraging.
BOOK REVIEWS
Architectural Acoustics. V. O. KNUDSEN. John Wiley and Sons, New York,
N. Y., 1932, viii + 617 pp., $6.50. This book is a comprehensive treatise on the
subject of architectural acoustics. It contains not only the results of the author's
own researches but also brings into one volume a general summary of the latest
developments in the field. It is so arranged that it should fulfill a long-felt need for
a text for university students, and at the same time serve as an invaluable refer-
ence for the acoustical engineer.
The book contains three main parts. Part one, on physical and physiological
acoustics, is so presented that even though the reader is not trained in the theory
of sound he should obtain a fair acquaintance with the fundamental principles
necessary for an adequate comprehension and appreciation of the fundamentals
of architectural acoustics. The second part of the book contains a thorough dis-
cussion of problems of reverberation, sound absorption, transmission, and insula-
tion of sound. Included in this part are tables giving the acoustical and physical
properties of a large number of materials. These tables, which are arranged
according to the general characteristics of the materials, are probably the most
complete and extensive of any so far published. The third part of the book is a
discussion of the application of the theory and principles of architectural acous-
tics to practically all types of buildings. A list of problems is included at the end,
which should increase the value of the book as a text.
Dr. Knudsen has in the publication of this book made a contribution to the
field of architectural acoustics that will be of value both to the student and to the
engineer. R. L. HANSON
Acoustics and Architecture. P. E. SABINE. McGraw-Hill Book Company,
Inc., New York, N. Y., 1932, vii + 321 pp., $3.50. The phases of acoustics that
are directly applicable to architectural problems make up the subject matter of
this book. It has been prepared especially for architects and others interested in
the practical aspects of the subject. The author, who has had many years of
experience in the subject, both inside and outside the laboratory, has chosen to
present the material in a way useful to a non-mathematical reader.
Acoustics is one of the oldest branches of physics, and relatively tremendous
advances in the subject have been made during the last fifteen years. But in
spite of this, it is still in some respects an inexact science. Theoretical investiga-
tions and the collection of practical data along many lines are desirable. In
pointing out the necessity for more accurate information on the one hand, how-
ever, the author emphasizes on the other hand that from a practical point of view
it is no longer necessary to be doubtful that the acoustical properties of a projected
auditorium will be tolerable.
Two-thirds of the book deal largely with the acoustics of auditoriums, and
treat of the properties of sound, reverberation, and sound absorption. The latter
third is devoted to noise in buildings and sound transmission through and in build-
444
BOOK REVIEWS 445
ing structures. Throughout the book emphasis is placed on experimental data,
in a large part obtained by the author at the Riverbank Laboratories. It might
be suggested that in the preface is to be found excellent advice to one attempting
to gain insight into the present state of practical acoustics. W. A. MACNAIR
Radio Engineering Handbook. Edited by K. HENNEY; written by a corps
of twenty-two engineers specialized in the various branches. McGraw-Hill
Book Co., New York, N. Y., 1933, 583 pp., $5.00. Although one might wonder
at first thought why the review of a radio engineering handbook should appear
in a journal devoted primarily to motion picture engineering, the identity of many
subjects in both branches of engineering justifies its appearance. Motion picture
engineering is an integration of a number of arts: excepting the mechanics and
the chemistry of motion picture engineering, the subjects of electrical trans-
mission, electroacoustical recording and reproducing, photoelectricity, electrical
measurements, etc., are common to radio and motion pictures. A topical resume
of the sections of the handbook in which motion picture engineers would be
interested will illustrate: Electric and Magnetic Circuits; Resistance; In-
ductance; Capacity; Complex Electrical Circuit Theory; Measuring Instru-
ments; Vacuum Tubes; Modulation; Audio Frequency Amplifiers; Rectifiers
and Power-Supply Systems ; Loud Speakers and Acoustics ; Television ; Fac-
simile Transmission; Photoelectric Cells; and finally, a section on Sound Mo-
tion Pictures, written by F. S. Irby.
The style of the work is typical of handbooks, the material being arranged
primarily for reference through the fairly extensive index provided. The hand-
book undoubtedly fills a long-felt need of engineers for a reference source in the
subjects listed above. S. HARRIS
SOCIETY OF MOTION PICTURE
ENGINEERS
OFFICERS
1933
President
A. N. GOLDSMITH, 444 Madison Ave., New York, N. Y.
Past-President
J. I. CRABTREE, Eastman Kodak Company, Rochester, N. Y.
Vice-Presidents
E. I. SPONABLE, Fox Film Corp., New York, N. Y.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
Secretary
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
Treasurer
H. T. COWLING, Rochester, N. Y.
Board of Governors
H. T. COWLING, 1430 Monroe Ave., Rochester, N. Y.
J. I. CRABTREE, Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
P. H. EVANS, Warner Bros. Pictures, Inc., 1277 E. 14th St., Brooklyn, N. Y.
R. E. FARNHAM, General Electric Co., Nela Park, Cleveland, Ohio.
O. M. GLUNT, Bell Telephone Laboratories, Inc., New York, N. Y.
A. N. GOLDSMITH, 444 Madison Ave;, New York, N. Y.
H. GRIFFIN, International Projector Corp., 96 Gold St., New York, N. Y.
W. C. HUBBARD, General Electric Vapor Lamp Co., Hoboken, N. J.
E. HUSE, Eastman Kodak Co., 6706 Santa Monica Ave., Hollywood, Calif.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
R. F. MITCHELL, Bell & Howell Co., 1801 Larchmont Ave., Chicago, 111.
E. I. SPONABLF. Fox Film Corp.. 850 Tenth Ave.. New York, N. Y.
446
COMMITTEES
447
W. T. CRESPINEL
W. V. D. KELLEY
W. C. HUBBARD
J. CRABTREE
J. I. CRABTREE
A. S. DICKINSON
G. EDWARDS
R. M. EVANS
T. FAULKNER
W. CLARK
O. B. DEPUE
D. M. BALTIMORE
B. W. DEPUE
C. D. ELMS
R. EVANS
E. R. GEIB
G. A. CHAMBERS
B. W. DEPUE
O. B. DEPUE
C. L. GREGORY
COMMITTEES
1933
Color
P. D. BREWSTER, Chairman
R. M. EVANS, Vice-Chairman
J. F. KlENNINGER
N. M. LA PORTE
Convention
W. C. KUNZMANN, Chairman
J. H. KURLANDER
Laboratory and Exchange Practice
R. F. NICHOLSON, Chairman
A. HIATT
D. E. HYNDMAN
E. D. LEISHMAN
C. L. LOOTENS
K. MAClLVAIN
D. MACKENZIE
Historical
C. L. GREGORY, Chairman
E. THEISEN, Vice-Chairman
N. D. GOLDEN
C. F. JENKINS
G. E. MATTHEWS
Membership and Subscription
H. T. COWLING, Chairman
W. H. CARSON, Vice- Chairman
J. G. T. GILMOUR
W. W. HENNESSY
J. KLENKE
W. C. KUNZMANN
E. E. LAMB
J. E. MCAULEY
Museum
E. THEISEN, Chairman
C. F. JENKINS
W. V. D. KELLEY
G. E. MATTHEWS
G. E. MATTHEWS
H. B. TUTTLE
M. W. PALMER
J. S. MACLEOD
R. F. MITCHELL
H. RUBIN
W. SCHMIDT
V. B. SEASE
J. H. SPRAY
O. NELSON
T. RAMSAYE
M. L. MISTRY
T. NAGASE
J. A. NORLING
N. F. OAKLEY
E. C. SCHMITZ
T. RAMSAYE
A. REEVES
F. H. RICHARDSON
A. F. VICTOR
448
COMMITTEES
[J. S. M. P. E.
A. A. COOK
W. B. COOK
H. A. DEVRY
E. GALE
Non-Theatrical Equipment
R. E. FARNHAM, Chairman
E. R. GEIB
N. B. GREEN
H. GRIFFIN
L. A. JONES
J. H. KURLANDER
R. P. MAY
R. F. MITCHELL
A. SHAPIRO
C. DREHER
P. H. EVANS
A. C. HARDY
E. HUSE
Papers
O. M. GLUNT, Chairman
G. A. CHAMBERS, Vice- Chairman
G. E. MATTHEWS
P. A. McGuiRE
D. McNicoL
W. C. MILLER
K. F. MORGAN
C. N. REIFSTECK
T. E. SHEA
H. T. COWLING
J. I. CRABTREE
Preservation of Film
W. H. CARSON, Chairman
A. S. DICKINSON
R. EVANS
C. L. GREGORY
T. RAMSAYE
V. B. SEASE
M. ABRIBAT
W. P. BIELICKB
L. BUSCH
F. CAHILL
A. A. COOK
G. A. CHAMBERS
Progress
J. G. FRAYNE, Chairman
C. DREHER
J. A. DUBRAY
R. E. FARNHAM
H. B. FRANKLIN
F. S. IRBY
E. E. LAMB
G. E. MATTHEWS
M. W. PALMER
G. F. RACKETT
P. SCHROTT
H. M. STOLLER
S. S. A. WATKINS
J. O. BAKER
T. BARROWS
G. C. EDWARDS
J. J. FINN
S. GLAUBER
Projection Practice
H. RUBIN, Chairman
J. H. GOLDBERG
C. GREENE
H. GRIFFIN
J. HOPKINS
W. C. KUNZMANN
R. H. McCULLOUGH
P. A. McGuiRE
R. MlEHLING
F. H. RICHARDSON
L. M. TOWNSEND
V. A. WELMAN
E. R. GEIB
H. GRIFFIN
J. H. KURLANDER
Projection Screens
S. K. WOLF, Chairman
W. F. LITTLE
A. L. RAVEN
R. T. RASMUSSEN
H. RUBIN
C. TUTTLE
May, 1933]
COMMITTEES
449
R. E. FARNHAM
H. P. GAGE
Projection Theory
A. C. HARDY, Chairman
W. F. LITTLE
W. B. RAYTON
C. TUTTLE
F. C. BADGLEY
B. W. DEPUE
Publicity
W. WHITMORE, Chairman
D. E. HYNDMAN
F. S. IRBY
W. C. KUNZMANN
G. E. MATTHEWS
D. McNicoL
M. C. BATSEL
P. H. EVANS
N. M. LA PORTE
Sound
H. B. SANTEE, Chairman
E. W. KELLOGG
C. L. LOOTENS
W. A. MACNAIR
W. C. MILLER
H. C. SILENT
S. K. WOLF
W. H. CARSON
L. E. CLARK
L. DE FOREST
J. A. DUBRAY
P. H. EVANS
R. M. EVANS
R. E. FARNHAM
C. L. FARRAND
Standards and Nomenclature
M. C. BATSEL, Chairman
H. GRIFFIN
A. C. HARDY
R. C. HUBBARD
L. A. JONES
N. M. LA PORTE
D. MACKENZIE
G. F. RACKETT
W. B. RAYTON
C. N. REIFSTECK
H. RUBIN
H. B. SANTEE
V. B. SEASE
T. E. SHEA
J. L. SPENCE
E. I. SPONABLE
S. K. WOLF
L. J. BUTTOLPH
R. E. FARNHAM
Studio Lighting
P. MOLE, Chairman
C. W. HANDLEY
R. F. MITCHELL, Chairman
B. W. DEPUE, Sec.-Treas.
Chicago Section
J. H. KURLANDER
W. J. QUINLAN
O. B. DEPUE, Manager
J. E. JENKINS, Manager
New York Section
P. H. EVANS, Chairman
D. E. HYNDMAN, Sec.-Treas.
M. C. BATSEL, Manager
J. L. SPENCE, Manager
Pacific Coast Section
EMERY HUSE, Chairman
G. F. RACKETT, Sec.-Treas.
C. DREHER, Manager
J. A. DUBRAY, Manager
SOCIETY ANNOUNCEMENTS
NEW YORK CONVENTION, APRIL 24-28, 1933
The semi-annual convention of the Society was held in New York, N. Y.,
April 24th-28th, with headquarters at the Hotel Pennsylvania. The success of
the-five- day meeting was due in large part to the efforts of Mr. W. C. Kunzmann,
chairman of the Convention Arrangements Committee; Mr. O. M. Glunt,
chairman of the Papers Committee, and his associates; and to the following
individuals and firms:
Mr. H. Griffin and Mr. H. Heidegger, of the International Projector Corp.,
for providing and installing the projection equipment; Mr. A. L. Raven, of
the Raven Screen Corp., for supplying and installing the projection screens;
the Bausch & Lomb Optical Co., for the projection lenses; the Blue Seal Sound
Products, Inc., for supplying the projection booth for the banquet hall; Messrs.
J. H. Spray and H. Mayer, of Warner Bros. Pictures, Inc., for providing entertain-
ment on the evening of the semi-annual banquet. Thanks are due Major Edward
Bowes, of the Capitol Theater; Mr. H. B. Franklin, of Radio City Music Hall;
Mr. H. Charnas, of Warner Bros. Strand Theater, for invitations kindly extended
to members of the Society to visit their respective theaters during the week of
the convention. Interesting film programs were provided for three evenings
at the hotel by the following companies: Columbia Pictures Corp., Fox Film Co.,
Metro-Goldwyn-Mayer, Inc., United Artists, Inc., Universal Pictures Corp., Mr.
W. J. Vanderbilt, and Warner Bros. Pictures, Inc. Credit is due also to Mrs.
E. I. Sponable for arranging an interesting program for the ladies attending the
convention.
At the luncheon which opened the convention on April 24th, addresses were
delivered by Mr. Terry Ramsaye, of the Motion Picture Herald; Mr. M. A.
Lightman, president of the M. P. T. O. A.; and Captain Paul Kimberley, of
England, bearer of a friendly message from the president of the British Kinemato-
graph Society to the Society of Motion Picture Engineers.
PROGRAM
MONDAY, APRIL 24TH
The morning was devoted to organization of the Convention, registration,
meetings of committees, etc.
12:30 P. M. Luncheon (for members and their families and friends).
Speakers: Mr. Terry Ramsaye, Mr. M. A. Lightman, Captain Paul
Kimberley (London}.
2:30 P. M. Business Session.
Opening of Convention; A. N. Goldsmith, President.
Report of the Secretary, J. H. Kurlander.
Report of the Treasurer, H. T. Cowling.
450
SOCIETY ANNOUNCEMENTS 451
Report of the Convention Arrangements Committee; W. C. Kunzmann,
Chairman.
Society Business.
3:00 P. M. General Session. PRESIDENT A. N. GOLDSMITH, Chairman.
"Application of Motion Picture Development in Other Fields;" O. H.
Caldwell, Electronics, McGraw-Hill Publishing Co., New York, N. Y.
"History of Animated Cartoons;" E. Theisen, Honorary Curator, Motion
Picture Collections, Los Angeles Museum.
"The Sound Film Program of the United States Department of Agriculture;"
R. Evans, Division of Motion Pictures, Department of Agriculture,
Washington, D. C.
"Audiphone — 'Out of the 'Silence;' " C. W. Barrell, Western Electric Co.,
New York, N. Y.
8:00 P. M. Lectures. PRESIDENT A. N. GOLDSMITH, Chairman.
"Unoccupied Motion Picture Fields" (Some Discoveries of the Payne Fund
Research); W. H. Short, Director, Motion Picture Research Council,
New York, N. Y.
"Photoplay Appreciation in the Nation's Schools;" W. Lewin, National
Council of Teachers of English, Newark, N. J.
Several interesting talking motion pictures were shown.
TUESDAY, APRIL 25TH
9:30 A. M. Studio Session. MESSRS. E. I. SPONABLE AND J. H. KURLANDER,
Chairmen.
"RCA Victor High Fidelity Film Recording Equipment;" S. Read, Jr.,
RCA Victor Co., Camden, N. J.
Report of the Progress Committee, Part I; J. G. Frayne, Chairman.
Report of the Studio Lighting Committee; P. Mole, Chairman.
Report of the Sound Committee; H. B. Santee, Chairman.
"The Preselection of Takes for Processing from Exposed Undeveloped
Negative;" D. W. Ridgway, RKO Studios, Hollywood, Calif.
"Professional Motion Picture Photography with High-Power Short-Life
Incandescent Lamps;" M. W. Palmer, Motion Picture Lighting Co.,
Long Island City, N. Y., and E. W. Beggs, Westinghouse Lamp Co.,
Bloomfield, N. J.
"Economies in Film Consumption by the Preselection Method;" G. Best,
Warner Bros. West Coast Studios, Hollywood, Calif.
2:00 P. M. Exhibition Session. MR. E. HUSE, Chairman.
"Radio City Sound Equipment;" B. Kreuzer, RCA Victor Co., Camden,
N. J.
Report of the Progress Committee, Part II ; J. G. Frayne, Chairman.
Report of the Projection Theory Committee; A. C. Hardy, Chairman.
Report of the Projection Screens Committee; S. K. Wolf, Chairman.
"A New AC Projection Arc;" D. B. Joy and A. C. Downes, National
Carbon Co., Cleveland, Ohio.
452 SOCIETY ANNOUNCEMENTS [J. S. M. P. E.
"Avoidance of Eye Fatigue;" F. H. Richardson, Motion Picture Herald,
New York, N. Y.
"Wide-Screen Photography with Cylindrical Anamorphosing System;"
H. S. Newcomer, Consulting Engineer, New York, N. Y.
"The Morgana Color Process;" J. A. Dubray, Bell & Howell Co., Holly-
wood, Calif.
"Sound Recording and Reproducing Using 16-Mm. Film;" C. N. Batsel
and J. O. Baker, RCA Victor Co., Camden, N. J.
8:00 P. M. This evening was left open for visits to local theaters.
WEDNESDAY, APRIL 26th
9:30 A. M. Photographic Session. MR. T. E. SHEA, Chairman.
"Sound Film Printing;" J. Crabtree, Bell Telephone Laboratories, Inc.,
New York, N. Y.
"Sensitometric Control in the Processing of Motion Picture Film in Holly-
wood;" E. Huse, Eastman Kodak Co., Hollywood, Calif.
"The Eastman lib Sensitometer as a Control Instrument in the Processing
of Motion Picture Film;" G. A. Chambers and I. D. Wratten, Eastman
Kodak Co., Hollywood, Calif.
"Some Properties of Two-Bath Developers for Motion Picture Film;"
J. I. Crabtree, H. Parker, and H. D. Russell, Eastman Kodak Co.,
Rochester, N. Y.
"An Improved Potassium Alum Fixing Bath Containing Boric Acid;" H. D.
Russell and J. I. Crabtree, Eastman Kodak Co., Rochester, N. Y.
"Directional Effect in Processing;" J. Crabtree, Bell Telephone Labora-
tories, Inc., New York, N. Y.
2:00 P. M. Projection Session. PRESIDENT A. N. GOLDSMITH, Chairman.
Report of the Projection Practice Committee; H. Rubin, Chairman.
"Image Distortion in the Projection and Viewing of Motion Pictures;"
C. Tuttle, Eastman Kodak Co., Rochester, N. Y.
7:00 P. M. Convention Banquet.
Dancing, Motion Pictures, and Entertainment.
THURSDAY, APRIL 27th
9:30 A. M. General Session.* PRESIDENT GOLDSMITH presented MR. J. I.
CRABTREE, Chairman.
Address of Welcome, by E. H. Colpitts.
"Recent Developments in Hill and Dale Recording" (with demonstration);
H. C. Harrison, Bell Telephone Laboratories, Inc., New York, N. Y.
"An Experimental Apparatus for the Projection of Motion Pictures in
Relief" (with demonstration); H. E. Ives, Bell Telephone Laboratories,
Inc., New York, N. Y.
Report of S. M. P. E. Fellow; "An Introduction to the Experimental Study
of Visual Fatigue;" P. Snell, University of Rochester.
* This session was held in the auditorium of Bell Telephone Laboratories, Inc.
May, 1933] SOCIETY ANNOUNCEMENTS 453
2:00 P. M. Standardization Session. MR. T. E. SHEA, Chairman.
"National Standardization in America;" P. G. Agnew, Secretary, American
Standards Association, New York, N. Y.
"S. M. P. E. Standardization Program;" L. A. Jones, Eastman Kodak Co.,
Rochester, N. Y.
Report of the Standards Committee; M. C. Batsel, Chairman.
"Wave Form Analysis of Variable Width Records;" O. Sandvik, V. C.
Hall, and J. G. Streiffert, Eastman Kodak Co., Rochester, N. Y.
"Analysis of Sound Quality with the Variable Density Method from Sensi-
tometric Data;" R. Schmidt and A. Kuester, Agfa Ansco Corp.,
Binghamton, N. Y.
"The Aperture Alignment Effect;" E. D. Cook, RCA Victor Co., Camden,
N. J.
8:00 P. M. Exhibition of recent talking motion pictures.
FRIDAY, APRIL 28TH
9:30 P. M. General Session. MR. T. E. SHEA, Chairman.
Report of the Committee on Non-Theatrical Equipment; R. E. Farnham,
Chairman.
"The Reproduction of Orchestral Music in Auditory Perspective;" J. Mill,
Bell Telephone Laboratories, Inc.
"Personality and the Voice;" Ivah L. Bradley, New York, N. Y.
"A Description and Demonstration of the Cine-Kodak Special;" O. Wittel,
J. Stoiber, and F. Tuttle, Eastman Kodak Co., Rochester, N. Y.
"Motion Pictures for Records and Teaching with the Cine-Kodak Special;"
H. B. Tuttle, Eastman Kodak Co., Rochester, N. Y., and R. P.
Schwartz, University of Rochester.
Report of the Museum Committee; E. Theisen, Chairman.
Report of the Committee on the Preservation of Film; W. H. Carson,
Chairman.
"A Non-Intermittent High-Speed 16-Mm. Camera;" F. Tuttle, Eastman
Kodak Co., Rochester, N. Y.
"Lightweight Single Film Recording System for Newsreels and Travelogues;"
C. R. Sawyer, Electrical Research Products, Inc., New York, N. Y.
2:00 P. M. General Session. PRESIDENT A. N. GOLDSMITH, Chairman.
"New Developments in Portable Gas-Electric Generators for Motion Picture
Lighting;" P. Mole, Mole-Richardson, Inc., Hollywood, Calif.
"Silenced or Silent Motion Picture Camera;" H. R. Kossman, Andre Debrie,
Inc., New York, N. Y.
"Military Training and Historical Films;" F. W. Hoorn, U. S. Signal Corps.
"A Triplex Moviola for Rerecording Editing;" J. Aalberg, RKO Studios,
Hollywood, Calif.
"Recording Equipment;" D. Canady, Canady Sound Appliance Co..
Cleveland, Ohio.
454 SOCIETY ANNOUNCEMENTS [J. s. M. P. E.
BOARD OF GOVERNORS
At the Board meeting held at the Hotel Pennsylvania, New York, N. Y., on
April 23rd, final arrangements for the Spring Convention, to begin the following
day, were completed. The final program as approved by the Board is given in
the preceding section.
Considerable attention was given by the Board to the various financial prob-
lems confronting the Society, and the desirability of revising the schedule of
membership charges. In view of the existing economic situation, it seemed to
be desirable that a certain degree of flexibility be allowed the Board in administer-
ing the fiscal affairs of the Society and to admit of adjusting the dues and other
charges conformably to the changing conditions of the times. The following
addition to By-Law VII was therefore framed for submission to the general
membership during the Convention:
Addition to By-Law VII
Sec. 7. The provisions of Sections 1 to 5, inclusive, of this By-Law VII, given
above, may be modified or rescinded by action of the Board of Governors.
At the meeting of the Society on the afternoon of Monday, April 24th, the
above addition to By-Law VII was unanimously approved.
The Sections 1 to 5, referred to in this new Section 7, are as follows:
SEC. 1. The entrance fees for all applicants shall be $10.00 for admission
to the grade of Active %iember, and $5.00 for admission to the grade of Associate
member.
SEC. 2. The transfer fee from Associate to Active grade shall be the differ-
ence between the above mentioned fees, or $5.00.
SEC. 3. The annual dues shall be $20.00 for Active members, and $10.00 for
Associate members, payable on or before October 1st of each year. Current or
first year's dues for new members, dating from the notification of acceptance in the
Society, shall be prorated on a quarterly basis, said quarters beginning October
1st, January 1st. April 1st, and July 1st. Nine dollars of these dues shall apply
for annual subscription to the monthly publication.
SEC. 4. Annual dues shall be paid in advance. All Active members in
good standing, who shall have paid dues for the preceding year, may vote or
otherwise participate in the meeting.
SEC. 5. Members shall be considered delinquent whose dues remain unpaid
for four months. Members who are in arrears of dues for 30 days after notice
of such delinquency, mailed to their last address of record, shall have their names
posted at the Society's headquarters which shall be the General Office, and notices
of such action mailed them. Two months after becoming delinquent, members
shall be dropped from the rolls if non-payment is continued.
A general discussion of the activities of the various committees of the Society
was held, in preparation for the joint meeting of the Board of Governors and
chairmen of committees to be held the following day, and described below.
With regard to the recent request of the Committee on the Development and
Care of Film that the name of the committee be changed in order that it be
more descriptive of the aims and functions of the Committee, the Board agreed
that the Committee should hereafter be known as the Committee on Laboratory
and Exchange Practice. Considerable discussion was also held concerning the
possibility of widely distributing among exchanges and exhibitors the test film
developed under the supervision of the Projection Practice Committee, presented
at this Convention in conjunction with the report of that Committee, and briefly
described in the Society Announcements sections of previous issues of the
JOURNAL.
The next meeting of the Board is to be held on July 14th.
May, 1933] SOCIETY ANNOUNCEMENTS 455
SUSTAINING MEMBERS
Bausch & Lomb Optical Co.
. Bell Telephone Laboratories
Burnett-Timken Laboratories
Eastman Kodak Co.
Electrical Research Products, Inc.
National Carbon Co.
RCA Victor Co., Inc.
HONOR ROLL
OF THE
SOCIETY OF MOTION PICTURE ENGINEERS
By action of the Board of Governors, October 4, 1931 , this Honor Roll was estab-
lished for the purpose of perpetuating the names of distinguished pioneers who are
now deceased;
LOUIS AlME AUGUSTIN L/E PRINCE
WILLIAM FRIESE-GREENE
THOMAS ALVA EDISON
GEORGE EASTMAN
JEAN ACME LE ROY
"Fi7m by Eastman"
. . . has never, to our knowledge,
appeared on the motion picture screen.
But a sufficiently informed public might
read those words between the lines that
introduce the majority of cinemato-
graphic masterpieces. Eastman motion
picture films . . . Super -sensitive "Pan,"
Sound Recording, Duplicating, and
others . . . enjoy a perennial, enviable
leadership, ably supported by the servic-
ing and distributing facilities of ...
J. E. BRULATOUR, INC.
New York Hollywood
Chicago
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
Volume XX JUNE, 1933
Number 6
CONTENTS
Progress in the Motion Picture Industry: Report of
Progress Committee
Page
the
459
Report of the Sound Committee
500
Report of the Committee on Standards and Nomenclature
Report of the Projection Screens Committee.
.... 505
510
Report of the Studio Lighting Committee
517
Report of the Projection Theory Committee
521
Report of the Committee on the Preservation of Film
523
Report of the Museum Committee
531
Officers
536
Society Announcements
537
Author Index Volume XX
539
Classified Index, Volume XX
541
JOURNAL
OF THE SOCIETY OF
MOTION PICTURE ENGINEERS
SYLVAN HARRIS, EDITOR
Board of Editors
J. I. CRABTREE, Chairman
A. C. HARDY
O. M. GLUNT F. F. RENWICK
Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.
Publication Office, 20th & Northampton Sts., Easton, Pa.
General and Editorial Office, 33 West 42nd St., New York, N. Y.
Copyrighted, 1933, by the Society of Motion Picture Engineers, Inc.
Subscription to non-members, $12.00 per annum; to members, $9.00 per annum,
included in their annual membership dues; single copies, $1.50. A discount
on subscriptions or single copies of 15 per cent is allowed to accredited agencies.
Order from the Society of Motion Picture Engineers, Inc., 20th and' Northampton
Sts., Easton, Pa., or 33 W. 42nd St., New York, N. Y.
Papers appearing in this Journal may be reprinted, abstracted, or abridged
provided credit is given to the Journal of the Society of Motion Picture Engineers
and to the author, or authors, of the papers in question. The Society is not re-
sponsible for statements made by authors.
Entered as second class matter January 15, 1930, at the Post Office at Easton,
Pa., under the Act of March 3, 1879.
PROGRESS IN THE MOTION PICTURE INDUSTRY*
Summary. — This report of the Progress Committee covers the period June, 1932,
to May, 1933. The advances in the cinematographic art are classified as follows:
(I) Cinematography, (II) Sound Recording, (III) Sound and Picture Reproduc-
tion, (IV) Film Laboratory Practice, (V) Applications of Motion Pictures, (VI)
Publications and New Books, (VII) Appendix.
In spite of the economic paralysis of the country during 1932, the
motion picture industry has steadily made progress. While it is
true that no spectacular advances can be reported for the past year,
there are numerous items showing progress in every branch of the
motion picture art. It is especially interesting to note that some of
the major items of progress during the past year have been in the
amateur field. This should augur well for the future of the industry
because it has been demonstrated time and again that an art that is
supported by an interested amateur element is sure to progress.
Some new film emulsions were announced during 1932, the most
interesting in the professional field being a new panchromatic film
possessing a high green sensitivity. The introduction of the 8-mm.
film in the amateur field called for a very fine-grained emulsion,
which has been satisfactorily used now for approximately a year.
In the field of sound recording were introduced new emulsions of
greater speed than the standard positive films heretofore used
almost exclusively in this kind of work.
Progress continued to be made during the year in the design of
new cameras, both professional and amateur. One company has
recently demonstrated to the industry a new silent camera embodying
many new and novel features. If this camera proves to be as good
as the claims made for it, it should rid the motion picture industry
of one of the severe limitations imposed upon it by the talking
picture; namely, the use of "bungalows" and "blimps" and other
undesirable attachments to a camera to make it sufficiently quiet
in operation on the stage.
During the past year considerable progress has been made in the
* Report of the Progress Committee. Presented at the Spring, 1933, Meeting
at New York, N. Y.
459
460 PROGRESS COMMITTEE [j. s. M. p. E.
use of transparent projected background processes. Some of the most
popular films released during the year contained a large percentage
of shots made in this manner. There has been a tendency during
the past year to substitute some accurate means of measuring ex-
posure on stages to replace the guesswork of the cameraman in
estimating the intensity of illumination of sets. An interesting
development in colored motion pictures during the year was the
application of color to cartoons. In the amateur field, the introduc-
tion of the 8-mm. film with the consequent reduction in the cost of
making amateur movies has tended to popularize the art more than
ever. The introduction of a rather simple additive color process in
this field has also widened the possibility of the use of color by the
amateur. Some progress has been reported in 16-mm. sound film
during the year, and certain standardizations in this field have been
agreed upon by the interested companies.
In the field of sound recording and reproduction, considerable
attention has been given during the past year to extending the range
of frequency of reproduced sound, the object being to achieve greater
fidelity of reproduction. While the introduction of the newer equip-
ment in studios and theaters has been delayed by economic diffi-
culties, it is expected that during this year great improvement will
occur in the quality of sound reproduced from film.
The application of motion pictures has advanced considerably
during the year in connection with scientific research, educational
work in schools and colleges, and timing devices of a high order of
accuracy.
There has been a considerable decrease in the use of dubbed foreign
versions for American pictures. Instead, American motion picture
companies have been developing their production abroad in order
to produce films in the native ^languages. The restrictions in certain
European countries against American films have been lessened or
considerably modified in various countries during the past year,
and the field for American motion pictures seems to be limited only
by the ability of the producers to make films of a sufficiently wide
appeal for the various peoples of the earth. The Society of Motion
Picture Engineers is naturally interested in the status of the motion
picture in Russia, where the industry has, of course, received spon-
sorship from the Soviet Government, and a special section of this
report deals with the condition of the industry in that country.
The Committee wishes to thank the various individuals and con-
June, 1933]
PROGRESS COMMITTEE
461
cerns that have supplied material for this report, and regrets that all
the institutions connected with the motion picture industry did not
see fit to supply information on their various contributions to the
art during the past year.
The illustrations shown in the report were obtained from the
Bell & Howell Co., Eastman Kodak Co., Electrical Research Prod-
ucts, Inc., General Electric Co., Ltd., RCA Victor Co., Inc., Weston
Electrical Instrument Corp., Western Electric Co., and Paramount
Publix Corp.
J. G. FRAYNE, Chairman
M. ABRIBAT W. C. HARCUS
W. P. BlELICKE F. S. IRBY
L. BUSCH E. E. LAMB
G. A. CHAMBERS G. E. MATTHEWS
A. A. COOK M. W. PALMER
J. A. DUBRAY G. F. RACKETT
R. E. FARNHAM P. SCHROTT
H. B. FRANKLIN H. M. STOLLER
S. S. A. WATKINS
SUBJECT CLASSIFICATION
CINEMATOGRAPHY
A . Professional
1. New Films and Emulsions
2. New Cameras and Accessories
3. Studio Illumination
4. Exposure Meters
5. Color
B. Amateur
1. General
2. New Emulsions
3. Cameras and Projectors
4. Color
II. SOUND RECORDING
1.
2.
3.
4.
5.
6.
General
New Recording Equipment
New Recording Methods
Microphones
Motor Systems '
Accessories
462 PROGRESS COMMITTEE [j. s. M. P. E.
III. SOUND AND PICTURE REPRODUCTION
1. New Sound Equipment
2. New Projectors and Accessories
3. 16-Mm. Sound-on-Film
IV. FILM LABORATORY PRACTICE
1. Film Development
2. Printers
3. Editing
V. APPLICATIONS OF MOTION PICTURES
1. Education
2. Race Timing Devices
VI. PUBLICATIONS AND NEW BOOKS
VII. APPENDIX
I. CINEMATOGRAPHY
A. Professional
1. New Films and Emulsions. — Two years have passed since the
new fast panchromatic negative emulsions were first introduced.
These materials are characterized by their fineness of grain, im-
proved color sensitivity, and increased speed, especially to incandes-
cent illumination. Sheet films were made available about the same
time for the still photographer. These were of two types: (a) a
panchromatic film of high total sensitivity and extreme red speed,
and (b) an "orthopanchromatic" film having a color-sensitivity
corresponding closely to that of the eye. The high-speed panchro-
matic emulsions introduced in 1931 for motion picture use were all
of the former type and are satisfactory for most purposes, both for
interior and exterior work. Occasionally it was found, however,
that with certain close-ups there was a tendency for over-correction
in the red which caused a false rendering of the flesh tones, par-
ticularly of the lips. An emulsion was, therefore, introduced during
the summer of 1932 that had properties similar to those of the second
type of sheet film emulsion. It is said to possess high green sensi-
tivity between 500 and 560 m/z and a reduced red speed compared
with the regular high-speed panchromatic cine negative materials.1
The cameraman is thus equipped now with a panchromatic emulsion
of the portrait type corresponding to that used by the portrait
photographer.
June, 1933] PROGRESS COMMITTEE 463
Several films for recording sound by both the variable density
and the variable width methods were introduced during the past
year that exhibited improved speed characteristics.2
Bloch3 summarized the recent advantages in emulsion making.
Several factors related to the cause of high sensitivity and fine
grain in modern panchromatic emulsions were summarized by
Fuchs,4 and details from patents were given concerning the newer
cyanine dyes. Stabilization and control of fog were shown to be
effected by the introduction of certain thiazoles and imidazoles
during manufacture.5
Courtesy of Photoplay Magazine
FIG. 1. Illustrating the use of composite photography in The Mummy.
Greater attention has been given during the past few years to the
testing of photographic emulsions, perhaps, than ever before, due to
the more exacting requirements of the studios. In keeping with
this trend, Baker6 has outlined various methods of testing, and has
described apparatus used with particular reference to motion picture
work.
The increased use (Fig. 1) being made of the transparent pro-
jected background process noted in last year's report has resulted in
the introduction of a special negative material for photographing
the scene to be used for the background. It is said to have very
fine grain and about the same speed and contrast as the regular
464 PROGRESS COMMITTEE [j. s. M. p. E.
negative film. About 65 per cent of the scenes in the Fox feature
State Fair were made by this process.
A double matte process for the introduction of foreground action
before a suitable background has been described by Williams, and is
stated to be a refinement of a process patented by him in 1918.
A dye-coated supersensitive panchromatic film is used in a bi-pack,
arranged emulsion to emulsion with another supersensitive panchro-
matic film. The actors are illuminated in the usual manner before
a blue background. Prints from the front negative are developed
and edited for selection of the scene to be used with the background
scene. The matte made from this print and the corresponding back
negative is used for printing in the action in the usual way.7
For making duplicate negatives, Crabtree and Schwingel8 recom-
mend developing the master positive to a relatively high contrast
VISUAL AND PHOTOGRAPHIC SPECTRA
A
2000 3000 4000 5OOO 6OOO 7000 8OOO 9OOO IOOOO
PHOTOGRAPHIC WITH QUARTZ BEFORE
CAN BE
PHOTOGRAPHED
IN VACUUM
PHOTOGRAPHIC 1904-1919
PHOTOGRAPHIC 1919-1935
PHOTOGRAPHIC 1925-1931
PHOTOGRAPHIC 1932-
Courtesy of Eastman Kodak Co.
FIG. 2. Illustrating advance of photography into infra-red region
of spectrum.
(gamma = 1 .85) and the duplicate negative to a low contrast (gamma
= 0.55) in order to insure low graininess in the final print. Prints
made from duplicate negatives of sound records were said to be
practically indistinguishable from original prints, although fre-
quency records showed some loss above 5000 cycles and a slight
increase of surface noise.
The greatest spectral extension of photographic sensitiveness
in the past quarter century occurred in 1932, as illustrated in Fig. 2.
Spectroscopic lines in the infra-red were recorded as far as 12,300 A
by Meggers of the U. S. Bureau of Standards. The list of specially
sensitized plates mentioned last year has been extended recently by
Mees.9 The chemical structures and spectra of infra-red sensitizing
dyes have been described by Brooker, Hamer, and Mees.10 Several
June, 1933] PROGRESS COMMITTEE 465
additional papers on photographic emulsions were published by
Carroll and Hubbard11 of the U. S. Bureau of Standards, the most
recent one dealing with variables in dye sensitizing.
Patents relating to emulsion manufacture disclosed among other
features a process of applying a color filter, which may later be
destroyed chemically, to an emulsion surface; a method of tinting
the picture areas of a sound and picture film, leaving the sound track
area untinted; and a method of coating a permanently translucent
light diffusing material between a slow sensitive and a fast silver
halide layer.12 Several other patents were issued relating to the
important subject of halation prevention.13 Processes using diazo
compounds as light-sensitive materials instead of silver salts con-
tinued to interest inventors but have thus far had very limited prac-
tical application.14
A patent was issued to Kupfer, whose metallic film bands were
mentioned in last year's review. The present disclosure describes
methods of reclaiming used film bands by removing the gelatin-
silver layers from the metal support. 15
2. New Cameras and Accessories. — An entirely new professional
35-mm. camera, said to operate silently, has been announced by
the Bell & Howell Co. (Fig. 3.) The film movement is of the type
employing two stationary registering pilot pins. The change from the
focusing to the operating position is accomplished by means of a
rapid-acting lever which controls the positioning of a ground glass
at the taking aperture, thus eliminating shifting of the camera.
The mounting of the lenses is unique in so far as the focusing is
controlled by a single knob at the rear right of the camera and only
one focusing dial is required for all lenses of focal lengths varying
from 24 to 150 millimeters. During focusing, the lens remains
stationary and the proper motion is imparted to the film mechanism
itself.
The design of the camera view finder is completely new, correction
being provided automatically for differences of parallax, and for
automatically correlating the adjustment of the finder lens with
the focusing of the photographic lens. The finder's field of view can
be adjusted with great precision to correspond to that of the taking
lens. The maximum aperture of the shutter is 180 degrees, and it
can be adjusted to lower apertures. The driving motor operates on
48-cycle 220-volt 3-phase current, runs cool and silent, and is en-
closed in the camera case.16
466
PROGRESS COMMITTEE
[J. S. M. P. E.
A sound camera of French make (Eclair) is claimed to be noiseless
and has the main sprockets of the picture and sound mechanisms
mounted on the same shaft, the driving motor being located in the
middle of the case between the sound and the picture heads. Thou-
sand-foot individual retort-type external magazines are used. A
four-lens turret is provided, but the focusing scale can be calibrated
for ten lenses, while a prismatic magnifying tube allows focusing
on the film.17
Courtesy of Bell & He
FIG. 3. New Bell & Howell silent camera.
A new camera (Tally's, of Los Angeles) embodies many unusual
features. The sprockets are not contained in the camera, but form
part of the light trap mechanism of the 1000-foot magazines (with
hinged covers) mounted below the camera body. Advantage is
taken of the lowered center of gravity by the pam-and-tilt move-
ment built as an integral part of the camera head, which is so balanced
that it will remain stationary in any position. The cam and shuttle
movement with pilot pin is said to be so silent that the camera does
June, 1933]
PROGRESS COMMITTEE
467
not require additional covering to dampen its running noises. Focus-
ing is accomplished by moving the entire four-lens turret, and is
followed on a ground glass inserted by levers into the film plane.
There is sufficient space for installation of a recording lamp and the
camera may be driven by any type of studio motor.
A new silent camera is made in Great Britain by W. Vinten, Ltd.
(Fig. 4), in which a claw and registering pin movement, driven from
one crank shaft, has eliminated cams and cam slots. The film gate
with film in place is moved away from the aperture part for focusing.
The threads of the spiral lens momenta are protected from dirt and
FIG. 4. The Vinten camera.
are designed to resist wear, while the lens is not revolved in focusing.
The sleeve for connection to the drive motor contains a "mechanical
fuse," which slips and makes a warning note in case the film jams.18
The Super Parvo camera (Debrie), made in France, is equipped
with inside magazines having a capacity of 300 meters of film.
Lenses are mounted in the conventional Debrie manner permitting
the use of lenses of all focal lengths. Focusing is done either directly
through the film or on a ground glass that can be switched to occupy
an exact position at the focal plane of the lens. The film mechanism
468 PROGRESS COMMITTEE [j. s. M. P. E.
is equipped with stabilizing pins and an intermittent pressure plate.
Care has been taken to make it silent in operation. The motor is
contained in the camera case and it is possible to interchange the
three types of motors recommended; namely, 220- or 110-volt
synchronous, or a 24-volt d-c. motor. The lens is protected by a
sheet of optical glass set precisely in front of it. The usual tacho-
meter, footage, and picture counters are part of the camera.19
While various manufacturers of cameras have been busily engaged
in developing a suitable silent camera for sound picture work, various
studios have been active in improving old "blimps" and designing
new ones to be used with the older cameras. One of the most success-
ful of these "blimps" is that now being used by Paramount at the
studio in Hollywood. The new Bell & Howell rotambulator20 is a
camera stand consisting of a carriage mounted on three wheels
and a columnar camera platform upright. The camera can be raised
from 18 inches from the ground to a 7-foot height while operating
or not. Both pam and tilt are controlled in operation through oil
viscosity insuring smoothness of operation. Pamming is controlled
by foot action and tilting by a conveniently placed hand lever.20
The last report mentioned two new types of "zoom" lenses for
motion picture work, which were marketed for the first time in 1931.
It was stated at that time that no account was available of the
results that were obtained with such adjustable focus objectives.
Three papers on the subject have appeared since then,21 and the one
published in the JOURNAL last October by Warmisham and Mitchell
gives a good summary of the uses to which the zoom lens can be
applied. The essential feature of all such equipment is that it be
mechanically rigid, and so made that the focal length can be changed
without disturbing the location of the precisely focused image on the
film.
A new so-called "zoom" lens is announced by O. Durholz, de-
scribed as giving smooth variations of 4x, or for 40- to 160-mm.
focal length, and as being focused without auxiliary lenses. The
lens weighs 5 pounds, and fits on the standard camera turret mount
without interfering with other lenses. The iris diaphragm is auto-
matically adjusted to maintain the effective aperture, which is //8
at full range and//5.6 at 3 x magnification.22
Little else can be said concerning new photographic objectives
except to note the usual number of patents on new constructions.23
The field of camera view finders has been definitely extended during
June, 1933] PROGRESS COMMITTEE 469
the past year by the application of new optical systems: there are
at least two finders now on the market that image the whole field
of a 25-mm. lens on a standard aperture. One of these is made by
Harrison & Harrison,24 the other by the Mitchell Camera Company.
A third, made by Beck in England and called the "Focostat," is
adjustable for all focal lengths of objectives from !3/8 to 8 inches.25
There is no new evidence that practical use is being made of
cylindrical lens systems in an effort to expand the screen picture in
the horizontal direction. There is still considerable interest in these
so-called anamorphosing systems, however, as the literature of the
past year shows. H. W. Lee has published an analysis of cylindrical
optical systems with particular reference to their application in
sound recording units.26 The perspective and distortion of cylindrical
elements has been discussed by Dr. G. Kogel,27 while Henry Dain
has written a lengthy account of the performance of Professor
Chretien's anamorphotic objectives,28 concluding with an argument
for their use to get a wider screen image from standard film. From
Dr. J. S. Watson, Jr., has come a different contribution to the sub-
ject, in which he explains the theory of the cylindrical Galilean
telescope and its use in the production of special photographic
effects.29
3. Studio Illumination. — There is little to report in the way of
progress in studio illumination in the United States. The General
Electric Company, Ltd., of London, advise that they have recently
introduced a new type of adjustable cradle for 2.3- and 5-kw. studio
projectors as shown in Fig. 5. In this cradle the back strut is ad-
justable so that the projector may be set at any desired angle. The
same company announces a portable photographic reflector which
employs a special 500-watt Osram photographic lamp. This lamp
has a small internally frosted pump and operates at a high efficiency,
producing an even light.
The General Electric Company also announces a new 2-kw. spot-
light which is only 12 inches in diameter and is fitted with an optically
worked parabolic mirror. It is said to be particularly useful where
there is not sufficient space to accommodate a larger spotlight. A
2-kw. Osram lamp having a flat filament is employed.
A British patent30 has been issued to Claude Neon Lights, Inc.,
on a process of producing white light for photography with panchro-
matic and orthochromatic films, the red rays from an electric dis-
charge lamp containing neon being blended with blue rays from a
470
PROGRESS COMMITTEE
[J. S. M. P. E.
discharge lamp containing mercury with or without neon or argon.
The blue rays are passed through a yellow or amber screen. It is
claimed that colors are not distorted, green being photographed as a
lighter gray than blue.
4. Exposure Meters. — A new exposure meter, manufactured by
the Weston Electrical Instrument Corp. of Newark, New Jersey,
makes use of the photronic photoelectric cell which converts light
energy directly into electrical energy without requiring any batteries
to furnish any additional power. Two of these cells are mounted in
Courtesy of General Electric Co., Ltd.
FIG. 5. Illustrating adjustable
cradle for studio projector.
the back of the instrument with covers that limit the angle included
by them to 60 degrees. The brightness of the scene that is to be
photographed is indicated directly on the scale of an instrument, and
these readings are translated into proper aperture and timing by use
of a cleverly designed calculator.
The calculator is arranged so that the basic film or plate speed may
be taken into account by an initial adjustment made at the time the
film is placed in the camera. The scene classification and the range
of film sensitivity are based upon the fundamental response of film
June, 1933] PROGRESS COMMITTEE 471
emulsions and are very useful to the photographer in analyzing his
scene and for obtaining the kind of negatives that he desires.31
5. Color. — Color cinematography has made rapid strides, despite
the curtailment of budgets on developmental work of all kinds
except those of exceptional promise of early liquidation. The appli-
cations have been sporadic due principally to the stringent demands
of economy that have militated against all matters involving cost.
There continues to be a demand for color particularly in the field
of short subjects and cartoons, and the advance in quality of photog-
raphy, definition, and color rendition, as evidenced by the several
subjects that have come to the screen, is very gratifying.
Two full-length features and several short subjects in Techni-
color were released during the year. These included four Silly
Symphony cartoons in Technicolor's new process which have met with
widespread approval and public demand. Greater realism was given
the characters by using one drawing per frame instead of the usual
one-to-four ratio.32
Cinecolor has announced a three-color process, which is described
as follows: prints are made on double-sided film, exactly as the
two-color prints are made; that is, with a basic dye color on one
side and a blue iron tone on the opposite side. The red dye used for
three-color work is of a magenta shade. To this double-sided film
is added, by imbibition, a yellow dye image, resulting in a three-
color effect. The camera has a beam splitter as used with two separate
films. One gate feeds down one film while a bi-pack is fed through
the opposite gate, producing three independent negatives. A matrix
transfer plate is made from the blue negative, and the transfer is
made in yellow to the double-sided film having the two-toned color
images.
The Spicer-Dufay process which was described in the report for
October, 1931, has recently been placed on a commercial basis.
A regular color line screen is used on the film base, with a panchro-
matic emulsion over the screen. Exposure is made through the sup-
port. It is stated that the manufacturers intended to supply 9.5-mm.
and 16-mm. widths as well as the professional standard 35-mm.
width.33
Three patents on methods of making bi-pack negative films
were published during the year.34 Anderson has covered a process
in which is used a double-coated negative having an orthochromatic
emulsion on one side over a filter layer and a panchromatic emulsion
472 PROGRESS COMMITTEE [j. s. M. p. E.
on the opposite side of the support. After development and bleach-
ing, the original orthochromatic side is dyed red, and the opposite
side is rolled with a fatty ink. The negative is then exposed through
the red dye on a suitable printing material and the fatty ink is trans-
ferred by pressure.35
Capstaff has described the preparation of a color image which
in its final form consists of a dyed gelatin relief image on top of an
image in an insoluble colloid layer.36 He also discloses a method of
producing a colored picture image and a neutral toned sound record
on the same film.37
Two patents are of interest which deal with methods of obtaining
two-color sub tractive prints.38 Two differently sensitized emulsion
layers are coated on a support. After exposure and development,
the images are bleached, mordanted, and dyed with a single dye.
The upper layer is then decolorized and converted to a complementary
color to the lower dye image The second patent describes a method
of successively coating and dyeing two layers on a single support.
Lawshe39 uses a double-coated film for printing two components
of a set of three-color record negatives, the third being printed
on a separate film which is cemented to the first film after the color
positives have been dyed in their appropriate colors. Three patents
were noted that dealt with means of obtaining color records using
the imbibition principle.40 Bleach-out layers are featured in several
patents on sub tractive processes.41 Thornton and Baker have each
disclosed methods for producing a color screen in connection with
additive processes of color cinematography.42
Inventive thought relating to lenticulated film processes has been
very active in recent years as evidenced by the comparatively large
number of patents issued. Methods of making embossing cylin-
ders,43 elimination of halation,44 preparation of filters,45 printing
sound records on embossed films,46 and projection of copies47 are
described. Eight disclosures were noted dealing with methods of
printing embossed films.48
B. Amateur Cinematography
1. General. — The past year has seen marked progress in the field
of amateur cinematography, both in the improvement of existing
apparatus and in the introduction of new materials and processes.
The two most outstanding advances have been the 8-mm. film
June, 1933] PROGRESS COMMITTEE 473
introduced by the Eastman Kodak Co. and the Morgana color
process introduced by the Bell & Howell Co.
2. New Emulsions. — A new non-halation super-speed pan-
chromatic emulsion for 16-mm. work was announced in October
of last year.49 A low-priced reversal stock was made available in
January, 1933, under the name Monofilm. Sufficient latitude for
average lighting conditions and a speed about equal to that of
orthochromatic film are claimed.50
The film used for the 8-mm. cameras described below carried a
Courtesy of Eastman Kodak Co.
FIG. 6. 8-Mm. camera.
different emulsion from that used on the already available 16-mm.
amateur standard films. Inasmuch as the area of the 8-mm. frame
is one-fourth that of the 16-mm. frame, and as a greater enlarge-
ment is encountered in projection, it was necessary to provide a very
fine grain emulsion for use in these cameras. This film has a color-
sensitivity comparable with that of the supersensitive film, but
because of the fine grain and resulting decrease in emulsion speed,
an exposure at //8 is required for open scenes in bright sunlight.
3. Cameras and Projectors. — No radical changes in the design of
474
PROGRESS COMMITTEE
[J. S. M. p. E.
16-mm. cameras for amateur use have been made, although several
types of professional cameras for film of this size have been intro-
duced. Two of these have been described by Stull.51 The Berndt
camera was designed with sound-on-film recording in mind, although
the camera described by Stull does not have this attachment. The
other camera described, the Arri camera, which is of German manu-
facture, is a silent camera for 16-mm. professional work only.
The Eastman Kodak Co. has announced a complete line of cameras
Courtesy of Eastman Kodak Co.
FIG. 7. Projector.
and projectors (Figs. 6 and 7) for a new size of substandard film,
8-mm.62 This equipment, for black-and-white photography only,
uses a film in the camera that is 16 mm. wide with half the per-
foration pitch of the present amateur standard film. During the
run through the camera, only one side of the film is exposed, after
which the roll is placed on the feed sprocket again ; and on the second
run through the camera the other side is exposed. After the reversal
June, 1933] PROGRESS COMMITTEE 475
development of the film, it is slit and cemented end to end. Thus a
25-foot original roll becomes 50 feet of 8-mm. film, which, because of
its smaller perforation pitch, is equivalent in screen projection time
to a 100-foot roll of the amateur standard film (Figs. 8 and 9).
Two models of cameras are available for this film, one carrying
Courtesy of Eastman Kodak Co.
FIG. 8. Comparison of several types of film, (a) Standard 35-mm. pro-
fessional film; (b) standard 16-mm. amateur film; (c) standard 16-mm.
amateur film containing four 4X5 mm. pictures per frame before cutting;
(d) standard 8-mm. amateur film.
a fixed focus unremovable //3.5 lens and the other a bayonet type
mount //1. 9 lens which may be replaced by longer focal length lenses
for telephoto work. Three types of projectors are listed. The
largest uses a 20- volt 100- watt lamp to project a screen image 40
inches wide. The other two models differ only in the illumination
source used. That for use on a 30-inch screen is equipped with a
476 PROGRESS COMMITTEE [j. s. M. p. E.
100-volt 100-watt lamp, while the smallest projector uses a 32-cp.
lamp for a 22-inch screen image.
The Weston Electrical Instrument Corp. has announced an
exposure meter similar to the one described previously but intended
primarily for amateur use. It is a simple instrument (Fig. 10)
consisting of a photronic photoelectric cell on the back of an instru-
ment movement. This cell is arranged with covers so that the angle
included is 60 degrees. The instrument is calibrated directly in
/ stops for ordinary cine panchromatic film at a speed of 16 frames per
second. Conversion tables are supplied for converting these readings
into proper exposure if different film is used or if a camera is used
that has a different frame per second speed.
Courtesy of Eastman Kodak Co.
FIG. 9. Reels of film of equal playing time.
Another exposure meter known as the Skinner Meter53 employing
a single photocell has also been placed on the market.
4. Color (16-Mm.)—The Bell & Howell Co. has announced
cameras and projectors for Morgana color, a two-color additive
process wherein the flicker usually associated with this type of
process has apparently been overcome by a very ingenious device.54
The camera has an oscillating arm between the lens and the film
into which the two-color filters are inserted. This shuttle carries
the filters back and forth before the film so that alternate frames are
exposed respectively to the two colors. The lens is opened one full
stop more than that required for black-and-white photography under
the same lighting conditions, and the camera is operated at a speed
of 24 frames per second.
June, 1933]
PROGRESS COMMITTEE
477
After the film has been processed by the usual reversal method
it is projected on a special projector for this type of film. The film
movement mechanism advances the film 2 frames, backs it up 1
frame, advances it 2 frames, etc. A wheel carrying the appropriate
projection filters is rotated before the lens in synchronism with the
film movement. Due to the special movement, the frames are
alternated on the screen at the rate of 72 pictures per second, al-
though the net rate of travel of the film is the same as in the camera;
namely, 24 pictures per second. As a result of the fact that each
frame is projected 3 times, and because of the high frequency of the
alternation of frames on the screen, there is no apparent flicker.
Courtesy of Weston Electrical Instrument Corp.
FIG. 10. Exposure meter for amateur use.
Although this is a two-color process, subject to the limitations
in color rendering common to such processes, and although rapidly
moving objects do produce a fringe, the process presents many
advantages for the 16-mm. field. It has been described completely
by J. A. Dubray at the 1933 Spring Meeting of the Society at New
York, N. Y.
Films made by a lenticular color process known as Agfacolor
were shown at the annual exhibition of the Royal Photographic
Society in September, 1932. The film support is covered vertically
with cylindrical embossings, 36 to the millimeter. Tri-color banded
filters are used before the //1. 5 or //1. 9 lens on the camera, and in the
lens system of the projector.55
478 PROGRESS COMMITTEE [j. s. M. P. E.
In the field of projection equipment for 16-mm. film, the trend
toward greater screen illumination that had previously been noted
has continued. The Victor projectors have had the optical system
improved,56 while the Bell & Howell Co. now provides a 400-watt
lamp in the type JL projector.
Two new printers for 16-mm. film have been announced. The
Arri printer is a step printer57 while the Wood- Watson58 is a con-
tinuous printer for sound film.
II. SOUND RECORDING
1. General. — The necessity of reducing costs of all sorts in the
studios during the past year has militated against the introduction
of new sound recording equipment on any extensive scale. However,
the producers of electrical sound systems have been active in intro-
ducing improvements in the older systems and in some cases com-
plete new recording outfits.
2. New Recording Equipment. — In the last report of the Com-
mittee brief mention was made of a new portable Western Electric
recording system. This system, which has recently been described59
in detail, has been in successful operation in several of the major
studios during the past year, and one of the units was taken to
Greenland with the Universal-Dr. Frank expedition for making
the new Arctic epic, S.O.S. Iceberg.
The Western Electric Co. has announced a simplified recording
amplifier system known as the type P system. This new system
consists essentially of one or more moving coil microphones located
on the stage, each of which is connected to a single-stage transmitter
amplifier located in the monitor room. These amplifiers are then
terminated by a mixer panel which in turn is connected to one or
more single-stage booster amplifiers in tandem as required to deliver
sufficient level to operate the final power amplifiers. The booster
amplifier and the mixer panel are also located in the monitor room.
The small current consumption of the transmitter and booster
amplifiers makes it possible to use small automobile storage batteries
for the filament supply and dry B batteries for the plate voltage.
Due to the small space required for these batteries, they can be
readily located in the monitor booth. The power amplifiers that
terminate the booster amplifier are located in the recording room
adjacent to their respective recording machines. These amplifiers
June, 1933] PROGRESS COMMITTEE 479
consist of a single stage of push-pull amplification and are all operated
by alternating current.
On comparing this system with the old amplifier system, it will be
noted that the large expensive A and B storage batteries, the battery
charging motor generators and the power board have been eliminated.
The room formerly occupied by these batteries, the amplifier room,
and the floor space for the battery charging motor-generators and
power board are no longer required. This arrangement admits of a
considerable saving in wiring and installation expense. All these
improvements have been obtained without interfering with the
flexibility of the recording system.
The RCA Victor Co. has introduced a new recording and re-
producing equipment designated as "high fidelity." The new
recording equipment is claimed to be capable of recording a range
of frequency up to approximately 10,000 cycles. Some of the other
improvements consist of a permanent magnet velocity microphone ;
a mixing panel in which operation noises have been reduced to a
minimum; a new recording amplifier, electrically superior to pre-
vious types, ruggedly constructed so as to withstand hard usage;
a new system of reducing ground noise, from which are omitted
the external shutters used heretofore with variable width sound
tracks. The new system utilizes a biased galvanometer method of
controlling the width of the transparent portion of the sound track.
The recorder is mechanically superior to previous models, which
results in extreme quietness of operation. A new optical system
of extreme simplicity and ruggedness is utilized employing a galvanom-
eter of the dry type and a much larger mirror than those used hereto-
fore. This results in less stray light, and assists in making the re-
finements required to record the higher frequencies accurately.
Electrical equalization for film and slit losses is provided in the
form of a separate panel incorporated in the standard recording
channel. This equalization results in a constant output from the
photocell of the reproducing equipment when prints of the sound
record are reproduced. The variable width symmetrical sound
track employed in the "High Fidelity" recording system is claimed
to have many advantages over the single-edged track previously
employed, among them being the attainment of a greater degree of
noise reduction. Fig. 11 illustrates the forms of single- and double-
edged tracks.
A new recording system is reported from Great Britain, the main
480 PROGRESS COMMITTEE [j. s. M. p. E.
feature of which is that the recording can be accomplished without
any electrical amplification whatever. The essential principle of the
invention is embodied in a circular panel of glass about two to three
inches in diameter, lined with a grid of mirror bands. A lamp throws
a beam of light through the strips of glass between the mirror bands,
which is focused down and received as a series of minute points of
light upon a small mirror oscillator.
This mirror oscillator may be controlled either by the usual
microphone and amplifier, or by direct speech. Its effect is to re-
direct the light received through the apertures between the mirror
strips on the glass tube back to the mirror strips. As the oscillator
works, more or less of the light impinges on to the mirror strips.
The light so received is reflected into the apparatus and focused
Courtesy of RCA Victor
Co., Inc.
FIG. 11. Single- and double-edged
variable width track.
on the film through the usual mil slits. The magnification depends
upon the number of mirror points employed in the grid.
This system, therefore, constitutes a recording apparatus con-
sisting simply of an optical system without any necessary electrical
amplifying device, as the amplifiers can be omitted because of the
almost unlimited degree of optical magnification. It is claimed
that this apparatus can be used for either the variable width or
variable density methods of recording.
While wax recording for motion picture purposes has greatly
declined in favor of film recording methods, the spectacular success
of the new vertically cut records made by the Bell Telephone Labo-
ratories is again focusing attention on this type of recording. These
June, 1933] PROGRESS COMMITTEE 481
records possess important advantages over laterally cut records.60
The electrical recorder and the reproducer used in the system have
also been greatly improved. "Cathode sputtering" has replaced
the old method of graphiting the wax, and a non-abrasive record
of cellulose acetate has replaced the abrasive record of the past.
These improvements have reduced the surface noises to the extent
of 25 to 30 db., and have increased the life of the record tremen-
dously. The volume range has been increased from about 25 or 30
db. to about 50 or 60 db., and the high-frequency cut-off has been
extended nearly an octave (to about 9000 cycles). A more faithful
reproduction has been obtained as a result of a natter frequency
characteristic and less non-linear distortion, so that sounds are more
distinct, lifelike, and clean-cut.
3. New Recording Methods. — One of the most important develop-
ments from the standpoint of economy of operation originated in the
Hollywood studios during the past year. This was the introduction,
first by Metro-Goldwyn-Mayer, of recording two sound tracks on a
35-mm. film, thus reducing the sound negative footage by 50 per cent.
Prints were then made which also carried two sound tracks. This
print was slit down the middle, producing two 17.5-mm. films, which
were then assembled for the "dailies" and run through the projection
machines in synchronism with the action. For final cutting of the
negative sound track it was, of course, necessary to split the sound
negative and treat each 17.5-mm. film as a single negative film.
This method has been adopted in varying degrees by many other
studios. Some continue to record only one sound track on the
negative, but make 17.5-mm. prints from this negative. Others
split the 35-mm. film before recording, and record directly on the
17.5-mm. film, using only one set of sprocket holes in pulling the film.
This requires a modification of the film recorders and developing
machines to handle the narrow film, whereas the original method
used by MGM does not require changes in recorders or developing
machines. Both systems require slight modifications of the pro-
jectors in order to accommodate the 17.5-mm. film. The narrow film
affects the theater only in cases of double film previews in which
the separate sound track is made on 17.5-mm. film.
Another method of saving raw stock without splitting the film
is to break down the negative before development and to develop
only approved takes, these being denoted by suitable punch marks.
The remaining raw stock is patched together and the opposite
482 PROGRESS COMMITTEE [j. s. M. p. E.
unused edge is used for printing the daily sound track. It is difficult
to make an offhand comparison as to the relative economies effected,
since the entire production technic is involved.
4. Microphones. — The tendency is away from condenser micro-
phones and their associated amplifiers toward dynamic permanent
magnet microphones. The lapel microphone also looms as a possi-
bility in certain kinds of recording, although its use to date has been
limited to public address systems.61
The ribbon microphone is a velocity operated pick-up device, in
contrast to other microphones which are pressure operated.62 It is
claimed that its directional properties offer the following operating
advantages: (1) the elimination of undesired interfering noises;
(2) the reduction of recorded reverberation; (3) bi-lateral sound
pick-up; (4) regulation of the extent of the sound pick-up by ad-
justing the angle of the source of sound with respect to the micro-
phone as well as the distance of the source from the microphone;
(5) the elimination of acoustic feedback in public address systems,
or from monitoring loud speakers by suitable angular-positioning
of the microphones with respect to the loud speakers; (6) the elimi-
nation of reflection difficulties in acoustical measurements.
Equipment for handling microphones has been improved but
slightly during the past year. The durable Mole-Richardson booms
continued to be widely used, and there were no outstanding improve-
ments in the smaller portable booms of the "dolly" type. One
studio has developed a smaller lighter boom similar in principle to the
Mole-Richardson boom, but designed to carry microphones of the
dynamic or ribbon type, which do not require closely associated
amplifiers. The use of "concentrators" of the reflector type has in-
creased, and some models which have been adjusted mechanically
or equalized electrically, are said to provide recordings that are not
readily distinguishable from those made with a standard micro-
phone. The reflectors vary in size from three to six feet in diameter,
and are installed in light hand-trucks in universal mountings. Con-
centrators are not often used on the stages because of undesired
reverberation effects. With reference to microphone placement,
there has been no material change in practices. In general, perspec-
tive is controlled by adjusting the average distance of the microphone
from the artist in order to obtain the desired effect.
5. Motor Systems. — In attempting to eliminate noisy gear systems
from camera motor assemblies, the MGM studio has experimented
June, 1933] PROGRESS COMMITTEE 483
with a direct connection of the shutter shaft of the camera to the
motor armature. In order to permit a direct connection of the
armature and shutter shaft, the motor speed must be 1440 rpm.
A four-pole three-phase synchronous motor, such as is generally
available, would therefore require a 48-cycle power supply, in the
form of suitable frequency-changing equipment operated by the
standard 50- or 60-cycle source of power. This has been accom-
plished experimentally in the MGM studios, using a 5 kw. 48-cycle
machine.
In order to assure synchronism with standard recording machines
having a drive-shaft speed of 1200 rpm., a six-pole 60-cycle 3-phase
synchronous motor can be used.
With a complete 3-phase synchronous motor system, such as
described, equipped with suitable starting reactors, phase correctors
and slip clutches in order to assure smooth starting, it is necessary
to provide a new system of synchronizing marks and scene identifica-
tions. At MGM an experimental system is based on a single master
control that starts all motors, illuminates the film in the recorder,
exposes a synchronizing mark on all sound and picture films, and
operates a "speed" signal. All this is accomplished during a four-
second interval. An additional synchronizing mark is automatically
placed at the end of each take. In conjunction with this system,
both edges of the recording stock are used for the sound record,
takes are identified by edge numbers on the film, and camera slates
are used only on the first scene of each roll of picture negative.
Title slates are made up independently, and are inserted when
the developed film is assembled into the ''daily."
6. Accessories. — The development of accessory apparatus and
technics for control and test purposes in sound recording has con-
tinued throughout the year. A new type of mixer control for dy-
namic microphones has been developed by the General Radio Co.,63
which is claimed to be noiseless in operation and to provide linear
attenuation up to 45 db. with logarithmic cut-off.
A simple rapid method of directly measuring the distortion in
audio-frequency amplifier systems has been described by Tuttle.64
III. SOUND AND PICTURE REPRODUCTION
1. New Sound Equipment. — Considerable progress has been made
during the past year in sound reproduction. The two major suppliers
of electrical equipment have announced systems that tend to im-
484
PROGRESS COMMITTEE
[J. S. M. P. E.
prove the overall quality of sound reproduction from film, the specific
improvements being an extension of the frequency range to lower
and higher frequencies than those previously reproduced, and an
improvement in the motion of the film past the scanning aperture
in the sound head.
The RCA Victor Co. has announced and installed in several
hundred theaters reproducing equipment capable of reproducing
sound at frequencies up to 9500 cycles. This equipment is extremely
simple and is operated entirely on alternating current. The sound
heads are of the drum type. There is no film gate, and no sliding
contact between the film and any parts in the sound head. This
feature is said to assure freedom from troubles during reproduction
LATERAL GUIDE
AND PRESSURE
ROLLER LATCH
SOCKET
CLAMPING RING
SOCKET
ELEVATIN6 RING
SOCKET
LOCKING SCREW
EXCITER LAMP .
SWITCH ON ENO
OF HOUSING
CONSTANT
SPEIO SPROCKET
FOUR
SPROCKET -HOLE
tOOP
Courtesy of RCA Victor Co., Photophone Div.
FIG. 12. Rotary stabilizer sound head.
due to wax and emulsion, and sprocket hole flutter, and to provide
the uniform motion of the film past the scanning light beam required
for satisfactory reproduction of the higher frequencies.
A photograph of the "rotary stabilizer" sound head for standard
series RCA Victor Photophone high fidelity reproducing equip-
ment is shown in Fig. 12. Four of these sound reproducing units
are used in the projection room of the RKO Roxy Theater, in New
York, N. Y.
Electrical Research Products, Inc., has announced a "wide range"
sound system. According to a report from this company the term
"wide range," as applied to the Western Electric sound system,
denotes a widened or increased frequency spectrum, and sometimes
June, 1933] PROGRESS COMMITTEE 485
an increased volume range. In terms of equipment, various ap-
paratus components are added to the system, or existing elements
are replaced ; although with few exceptions this treatment does not
involve what may be considered major apparatus developments.
The new 596 loud speaking telephone (Bostwick receiver), which
has been described elsewhere at some length in technical papers, and
the T A -41 51 loud speaking telephone, are additions to the loud
speaker equipment already installed where a wide range conversion
is to be made. These instruments have already acquired the sig-
nificant popular names of "tweeter" and "woofer," respectively.
The new curved reproducer gate (T A -7 260 aperture), which will be
described separately, represents development by ERPI that was
necessary before satisfactory wide range reproduction could be
offered from sound film. The other material used embraces equal-
izers, coupling networks for dividing the loud speaker circuits, heavy
baffles for mounting the "woofers," and various auxiliary equipment,
such as power relays and the like.
It is perhaps noteworthy, as regards the application of wide range
conversion equipment to all Western Electric sound reproducing
systems now in use, that special attention has been given to obtaining
an over-all standard result among the various types without involving
the licensee in the expense of junking his equipment wholesale or
replacing apparatus that is in good order. Customers have the
option of modernizing their installations, however, as in such cases,
for example, where early types of sound reproducers and storage
batteries are in use ; if desired these will be replaced at nominal charges
with reproducer and power unit equipment of the latest types.
This latter treatment, where it applies, so reduces current mainte-
nance costs that the idea is very attractive and proving popular.
The new aperture referred to above consists of a cast frame sup-
porting a lens tube assembly, a curved film-supporting surface to
guide the film past the scanning lamp beam, and a freely running
flanged guide roller to maintain the film in lateral alignment. A
sliding frame opened and released by a self-locking cam on the main
frame supports two film shoes that hold the film against the guide
roller and the sound sprocket, respectively.
All frictional contact with the film, both at the curved gate and at
the two pressure shoes, is on the base side, leaving the emulsion side
of the film open. Consequently, there is little opportunity for ac-
cumulations of emulsion to form.
486 PROGRESS COMMITTEE [j. s. M. P. E.
While easier to thread and simpler to maintain than apertures of
the older type, the greatest advantage of the new design is the reduc-
tion in 96-cycle flutter that modulates the higher frequencies and
causes a quality of reproduction commonly described as "fuzziness."
The recent introduction of wide range makes this new aperture
particularly timely, since the broadening of the frequency band at
the two ends of the spectrum imposes more severe requirements on
the reproducing equipment, especially as regards the prevention of
flutter. The new unit has consequently been made standard for all
wide range installations.
2. New Projectors and Accessories. — In addition to the changes in
reproducing equipment that benefit sound reproduction, improve-
ments have been made in the general operation of projection equip-
ment. For example, the International Projector Corp. introduced
the Simplex-Acme change-over device in 1932. By means of this
device, which is attached to the douser control of the Simplex- Acme
projector, and by the pressure of a switch on either projector, the
douser of the incoming projector is opened and that of the outgoing
projector is closed. At the same instant, however, the sound is
changed from the outgoing projector to the incoming projector by an
electromechanically controlled device attached to the amplifier
switch. The change-over is claimed to be made without electrical
disturbance in the sound system and, of course, is instantaneous.
Projection objectives have been changed very little during the
year. The Dallmeyer firm has announced a new lens series called
the Superlite, having a speed of //.1. 9 for which a 33 per cent in-
crease in illumination is claimed.65 An analysis by W. B. Rayton66
of the optical systems used in short-focus lenses for projectors be-
hind the screen has appeared in the JOURNAL. One new ob-
jective of this type has been patented.67 R. F. Mitchell has con-
tributed an interesting article on keystone distortion as produced by
projectors at varying angles from the normal to the theater screen;68
from the diagrams that illustrate the article the cameraman can de-
termine to what extent his work will appear distorted when shown in
the theater.
Non-intermittent projectors are still being discussed,69 it appears,
without arousing much active interest except among examiners in the
Patent Office.70 The same is true for stereoscopic apparatus,71
and in this case the list of patents is a large one.72 For the benefit
of those who did not hear Dr. Ives' thorough exposition of the subject
June, 1933] PROGRESS COMMITTEE 487
of stereoscopic projection at the October, 1931, meeting of the Society,
his paper has appeared in the JOURNAL.73
3. 16 -Mm. Sound-on- Film. — A certain amount of progress has
been reported in the recording and reproduction of sound on 16-mm.
film during 1932. Although no discoveries or inventions have been
reported that tend to modify or obviate the limitations imposed
by the slow linear motion of the film, an agreement by several
manufacturers of amateur equipment on certain standards should
result in a wider use of this medium.
Under this agreement, it has been decided to retain the 16-mm.
width but to dispense with one row of perforations. The size of the
picture will remain unchanged. The sound track will be 0.065
inch wide with its central line midway between the edge of the film
and the side of the frame. A standard projection speed of 24 frames
per second has been agreed upon, and the lead of the sound gate
has been set at 25 frames. Standards embodying the details given
above have been adopted and published by the Society.74
The RCA Victor Co. has announced a new 16-mm. sound-on-film
projector utilizing a 400-watt projector lamp, a number of which
machines are in commercial use for advertising and educational
purposes. A number of large national advertisers have utilized 16-mm.
sound motion pictures for personnel and consumer education on their
products.
An important step toward the development of the non-theatrical
sound motion picture field was made by the RCA Victor Co. in
establishing a 16-mm. sound-on-film library. The film subjects in
this library are classified as Detective Stories, Aviation, Animated
Cartoons, Sports, Travelogues, Comedies, Music Appreciation,
etc. Burton Holmes Lectures, Inc., foremost producer of the travel-
ogue type of screen subject, is producing additional subjects for
the 16-mm. sound-on-film field from a large library of available
negatives.
IV. FILM LABORATORY PRACTICE
1. Film Development. — An improved process of developing film
and the apparatus required for it have been developed by the Roy
Davidge Film Laboratory, in Hollywood. The developing tank is
semi-cylindrical, its axis being horizontal. Two wheels serve as reels
on which the film is wound, the wheels being mounted on a con-
488 PROGRESS COMMITTEE [j. s. M. P. E.
centric false drum coaxial with them. This false drum is removed
after the film is mounted on the reel, causing the upper layers of the
film to press together. One of the novel features of the method is
the use of a celluloid spacing strip between adjacent layers of film,
which is embossed in such a manner that dome-shaped protuberances
project from each of its surfaces. It is claimed that these pro-
tuberances break up the flow paths of the developer, resulting in a
film free of streaks, chemical and directional effects, and under-
developed areas.
2. Printers. — The new Bell & Howell automatic printer,75
described in last year's report, has undergone extensive tests at the
MGM laboratory. The optical system has been improved, increasing
the illumination and thereby allowing the printing aperture to be
still further reduced. This in turn increases the definition of both the
picture and the sound track on the prints. A special rheostatic
control has been inserted in the lamp circuit consisting of two parts,
one allowing a coarse adjustment in 2-volt steps, the other a final
adjustment in 0. 2-volt steps.
The Horsley Laboratory of Hollywood has devised an attachment
for the standard type D Bell & Howell printer which reduces the time
and labor involved in making composite prints. The sound track is
printed simultaneously with the picture, using a supplementary
drum situated between the main gate and the lower take-up reels.
The negative may be used either "head first" or "feet first." A re-
recorded sound negative having constant transmission throughout
is required as only one printing light is available.
A new rotary printer has been developed by a British firm76 which
is claimed to have unusually high printing accuracy, and consists
of a unit that is completely independent of both mechanical and
electrical considerations. Both the light changes and lamps are
operated by power generated by the driving motor which runs
at constant speed on alternating current mains. Due to the unvary-
ing current supply and the constant speed of the machine, the film
densities remain constant over the entire working day.
A perfect contact between the two films is achieved by the curva-
ture of the gate on the top of the light box, and tension is supplied
to the positive film only. Uniform transmission of the film is at-
tained by means of a patented mechanical filter that drives the pre-
cision sprocket, the latter having an involute tooth cut to a special
depth to take two films.
June, 1933] PROGRESS COMMITTEE 489
Rewinding the negative is avoided by using a forward and reverse
chart control band. No stapling, notching, or other damage of the
negative is necessary with this light control system, although the
printer can work with negatives so treated. The densities are
recorded on a parchment chart 70 mm. wide, which is placed in the
printer at the start and is automatically synchronized by the ma-
chine. The composite machine, when locked together by the gear-
box, produces picture and track at one run of the negatives at a speed
of 1 00 feet per minute.
A new process in studio "dissolve" work is claimed by a British
laboratory.77 This is accomplished efficiently and inexpensively
by making a duplicate negative by an optical method from the two
original negatives that have been dissolved into one another. The
new negative exactly matches the originals, but contains the dissolve
made exactly in t he right place, so that there is no loss of synchronism
when it is subsequently wedded to the sound track. The dissolve is
perfectly smooth and entirely free from the flicker often found in
chemical dissolves.
3. Editing. — A new film cutting and editing machine, capable
of handling either single or double film has been developed and pro-
duced by the Western Electric Co., Ltd.78 (Fig. 13.) The machine,
which will furnish high-quality reproduction either by head tele-
phones or loud speaker, incorporates a novel viewing mechanism
that passes the film through the picture gate at constant speed.
The stationary picture is obtained by means of rapid flashes of light
from a neon lamp located below the picture gate, which occur in
synchronism with each picture frame as it passes the view finder.
V. APPLICATIONS OF MOTION PICTURES
1. Education. — The use of talking motion pictures for educational
purposes has been discussed widely for several years, but it remained
for the University of Chicago, under the able leadership of President
R. M. Hutchins, cooperating with E. R. P. I. Motion Picture Con-
sultants, Inc., to initiate the production of educational pictures to be
used as an integral part of the general courses for freshmen and
sophomores.
During 1932, two films of the physical science series were made,
covering the subjects of oxidation and reduction, and the molecular
490
PROGRESS COMMITTEE
[J. S. M. P. E.
theory of matter. In these films the off-stage method of explanation
is used throughout. It is planned to produce 20 films in the physical
science series and a similar number in the biological and social
sciences and in the humanities.
The use of motion pictures in astronomical work continues un-
abated. A description of a motion picture of the moon made at the
Treptow Observatory is published in Filmtechmk. Single frame
exposures, each lasting from 1/4 to l/z second, were made at intervals
•BBBMHH
FIG. 13.
Courtesy of Western Electric Co., Ltd.
Cutting and editing machine.
of 5 seconds, giving for the duration of the 31/z- hour eclipse a pro-
jection time of I1/ 2 minutes at 24 frames per second.
The introduction of sound equipment in schools during 1932 was
retarded considerably by current economic conditions. Some of
the more progressive schools managed to install sound equipment,
one of the outstanding installations being that made at the Samuel
Gompers Industrial High School in New York City.79
2. Race Timing Devices. — Apart from the progress made in the
June, 1933] PROGRESS COMMITTEE 491
use of motion pictures in educational and medical fields, the most
outstanding application of general interest in 1932 was the use of
this medium in connection with the timing of track events at the
Olympic Games in Los Angeles.80 A 16-mm. Bell & Howell camera
was arranged so that it photographed simultaneously, at 128 frames
per second, the finish of the race and the dials of a clock driven by a
synchronous motor at a speed of 10 rpm., the motor in turn being
driven by a 200-cycle tuning fork generator. The clock face consists
of three rotating dials, the inner dial rotating at one revolution per
second, and having one hundred divisions. The middle dial, having
60 divisions, rotates at one revolution per minute; and the outer
dial, also having 60 divisions, rotates at one revolution per hour;
thus making it possible to read minutes, seconds, and one-hundreths
of a second. The clock is automatically started, from a pre-set zero
position, with the closing of a switch built into the starter's pistol
and closed when the trigger is pulled.
Along this same line the Bell & Howell Co. has announced a micro-
motion camera consisting of a "Filmo" camera mounted in con-
junction with an optical system that permits photographing a
chronometer at the same time as the action for time-study cine-
matography. A lamp house is an integral part of the optical system,
and illuminates the chronometer and a title card, the images of which
are reflected in the field of a 1- or 2-inch photographic lens. A focus-
ing device permits maintaining the sharpness of the images of the
chronometer and title for any distance of the object being photo-
graphed.
The U. S. Navy continued during 1932 the active use of motion
pictures in the general scheme of the Naval organization, touching
on its entertaining, instructional, and recruiting value. For entertain-
ment alone the Navy owns, in duplicate, 467 features, and is acquiring
monthly an average of 25 features and 5 short subjects.
The Academy of Motion Picture Arts and Sciences has partici-
pated actively with the War Department in mapping out a course
of study of the production of talking motion pictures. The Signal
Corps of the U. S. Army has assigned Capt. M. E. Gillette to Holly-
wood for six months to participate in this study.
Among the activities of the Academy of interest to the Society are
the formation of committees studying the establishment of an effec-
tive uniform practice as regards the length of reels, the revision of
standard release print make-up, methods of improving the average
492 PROGRESS COMMITTEE [j. s. M. p. E.
quality of release prints, establishment of uniform screen illumination
in studio reviewing rooms, investigation of film preservatives, and
elimination of blimps through development of a silent camera.
VI. PUBLICATIONS AND NEW BOOKS
A well-known exhibitor's publication, the Bioscope (London),
was incorporated with Kinemato graph Weekly (London) and the com-
bined issue published in an enlarged format. The section of this
publication devoted to the theater is now issued separately as the
Ideal Kinema and Studio. Another journal was added to the growing
list for the cine amateur under the name Home Movies (London).
A quarterly publication containing articles related to the use of
motion pictures in biology was initiated during 1932. It is called
The Journal of the Biological Photographic Association (Baltimore).
A useful compilation of publications and books concerned with
cinematography was published by G. E. Matthews.81 A list of the
principal books appearing since the last report of the committee
follows :
1. Year Book of Motion Pictures— 1933 , 15th Edition, Film
Daily, New York.
2. Motion Picture Almanac — 1932, edited by Motion Picture
Herald, Quigley Publishing Co., New York.
3. Kinematograph Year Book — W33, Kinematograph Publica-
tions, Ltd., London.
4. General Annual of Cinematography — 1932-1933 (Annuaire
Generate de la Cinematographic 1932-1933), Cine- Magazine, Paris.
5. Yearbook of Photography, Cinematography, and Reproduction
Processes for the Years 1928-29 (Jahrbuch fur Photo graphie, Kine-
mato graphie fur die Jahre 1928-29), Vol. 31, Pt. 1, edited by J. M.
Eder, W. Knappe (Halle).
6. Sensitization and Desensitization (Sensibilisierung und De-
sensibilisierung) . This is Vol. 3, Pt. 3, of Ausfuhrliches Handbuch
der Photographie, edited by J. M. Eder, W. Knappe (Halle).
7. The Photographic Objective (Das Photo gr aphis che Objectiv);
The Theoretical Basis of the Photographic Process (Das Theoretischen
Grundlagen der pho to gr aphis che Prozesse); Scientific Applications
of Photography (Wissenschaftliche Anwendungen der Photographie).
These are Vols. I, V, and VI, Pt. 1, respectively, of Handbuch der
Wissenschaftlichen und Angewandten Photographie, edited by A.
Hay (9 vols.), J. Springer, Vienna.
June, 1933] PROGRESS COMMITTEE 493
8. Cinematography and Talkies, by J. R. Cameron and J. A.
Dubray, Cameron Publishing Co., Woodmont, Conn.
9. Introduction to Sound Photography (Einfuhrung in die Ton-
photographie) by J. Eggert and Richard Schmidt, S. Hirzel, Leipzig.
10. Fundamentals of Sound Films (Die Grundlagen des Tonfilms),
by F. Skaupy, Union Deutsche Verlags., Berlin.
11. The Film in National Life, edited by Sir Benj. Gott, Allen
and Unwin, Ltd., London.
12. The Amateur Cine Movement, by Marjorie A. L. Burgess,
Sampson, Low, Marston & Co., Ltd., London.
13. Motion Pictures and Lantern Slides for Elementary and Visual
Education. A compilation by H. E. Brown and J. Bird, Lincoln
School Teachers College, New York.
14. Making Better Movies, by A. L. Gale and R. C. Holslag,
Amateur Cinema League, New York.
15. The Principles of Optics, by A. C. Hardy and F. H. Perrin,
McGraw-Hill Book Co., New York.
16. Photocells and Their Application, by V. K. Zworykin and E.
D. Wilson, John Wiley & Sons, New York.
17. Report of the VIII International Congress of Scientific and
Applied Photography (Bericht uber den VIII Internationalen Kongress
fur Wissenschaftliche und Angewandte Photo gr aphie) , Dresden, 1931,
A. Barth, Leipzig.
18. Acoustics and Architecture, by P. E. Sabine, McGraw-Hill
Book Co., New York.
19. Advances in Physical and Technical Acoustics (Fortschritte
der physikalischen und technischen Akustik), by F. Trendelenburg,
Akad. Verlags., Leipzig.
20. Sound Film Reproduction (Tonfilmwiedergabe), by R. Dahl-
green, Union Deutsche Verlags., Berlin.
VII. APPENDIX
A . General Field of Progress of the Motion Picture Industry in Great
Britain
The year 1932 has been an uneventful one, for the need of re-
trenchment resulting from economic conditions has had its effect
upon the industry. It has failed to produce any outstanding de-
velopment in new equipment or technical accessories.
What progress has been made has been largely concerned with the
refinement of technic in recording sound and in production methods
494 PROGRESS COMMITTEE [J. S. M. p. E.
brought about by a growing realization of the need of higher
standards than in the past.
Notwithstanding prolonged economic depression and high taxa-
tion, certain advances are taking place in the film industry in Great
Britain. Developments not only in the construction and the opera-
tion of theaters, but also in the production and preparation of films,
have been progressing along sane and economic lines. While there
have been no drastic changes in screen technic, progress has been
constant, so that in spite of a severely restricted foreign market for
the films, the British industry stands in a favorable position.
An examination of the new theaters shows that, generally speaking,
the average capacity lies approximately between 1500 and 2000
seats, although the latter figure has been exceeded in the case of the
Gaumont Palace at Lewisham with its 3300 capacity, and the
Gaumont Palace at Hammersmith with its 3600. Others completed
during the year hold from 2500 to 3000, and one is now being
built in London which will hold 4000. The theaters are being very
much better planned, and allowance is being made in the majority
of cases for expansion if the business continues to progress in the
same ratio as in previous years.
It is probably in connection with the interior decoration of the
cinema that the greatest progress has been made, and considerable
attention is paid in designing the building to permit the use of
absorbent materials in order to take care of the acoustic properties of
the theater.
Probably one of the most outstanding occurrences of the year was
the inauguration of the new Gaumont British Studios at Shep-
herds Bush, London, which provide extensive facilities for production
work. Built on the site of the old 1914 building of the original
Gaumont Company, the new studios were opened in July.
The available floor space of the new studio blocks is over 80,000
feet and, in addition, there is another block to house additional
studios, executives, workshops, etc. There are five large studios, the
largest of which is 85 feet wide and 136 feet long. Each is provided
with the fullest service accommodation. The overhead lighting is
suspended from trolleys on a system of runways, enabling lamps to be
centered or banked as desired. Galleries at two heights facilitate the
direction and placing of the lighting equipment. In addition to the
space already mentioned, an adjoining building houses the film print-
ing laboratory, which handles over 2,000,000 feet of film per week.
June, 1933] PROGRESS COMMITTEE 495
A total number of 153 British made films were shown to the trade
in England during 1932, as compared with 139 during 1931. Ameri-
can features shown to the trade decreased from 490 to 449, and Conti-
nental films increased from 38 to 39. Of the total of 641 films shown,
only two were silent.
The Ministry of Agriculture is using films for publicity and propa-
ganda purposes in connection with the National Mark scheme of
marketing, distributed by Daylight Talking Picture vans employing
16-mm. equipment. The War Department, the Air Force Depart-
ment, and the Admiralty have continued to use training films, and
further developments are anticipated. The General Post Office is
developing a scheme of telephone advertising through films.
B. Progress in Motion Pictures in U. S. S. R.
As a result of the recent reorganization of the Soviet film industry
and the consequent extensive production plans, raw film require-
ments of the Soviet Union are estimated, under the second five-year
plan, to be 1,240,000,000 feet of raw film annually for the coming
five years, according to a report based on Soviet sources to the
motion picture division of the U. S. Department of Commerce.
Production capacity of existing raw film factories does not exceed
75,000,000 meters annually, it was stated. A new factory is reported
being built near Kazan, with an estimated yearly production of about
150,000,000 meters. This factory is scheduled to be completed
in 1934. Another factory having a yearly production of 200,000,000
meters is to be built in the near future. This unit will specialize in the
production of more rare and expensive types of raw film.
There are at present 14 film studios in Soviet Russia, located at
or in the vicinity of Moscow, Leningrad, Odessa, Kiev, Yalta, Tash-
kent, Aschkhabad, Stalinabad, Tiflis, Baku, and Erivan. Five
factories manufacture apparatus for the production of sound and
silent films.
At present there are about 1245 regular picture houses located in
cities, having a total seating capacity of 535,000, or about 70 in-
habitants per seat. Under the five-year plan it is proposed to in-
crease the total capacity to 1,200,000 by 1937, or to about 40 inhabi-
tants per seat. The plan further provides for the creation of 42,500
traveling cinemas for villages, with shows to be organized once every
10 days in villages of 100 to 200 inhabitants, and twice in 10 days
in villages with 1000 to 2000 inhabitants.
496 PROGRESS COMMITTEE [J. S. M. P. E.
It is proposed to produce talking pictures in the languages of the
47 different nations and tribes of Soviet Russia, Ukrainians, Tartars,
Georgians, Kalmucks, and others, by "dubbing" Russian sound
films.
Sound in Soviet Russia. — There are two major Russian sound
systems which are entirely Russian in origin and manufacture, the
Shorin and the Taguer. The outstanding characteristic of the Shorin
recording camera is that it may be used to produce a variable width
or variable density sound track. The recording unit is a single
string galvanometer, normally used with the ribbon parallel to the
sound track, and thereby producing a variable width track. It may,
however, be rotated through 90 degrees, thereby producing a track
of the variable density type. The Taguer system uses the Kerr Cell
for recording, and the apparatus is manufactured by the Electrical
Research Institute in Moscow. Both systems use the Reisz carbon
microphone, of German origin.
C. Progress Notes from Miscellaneous Countries
The language difficulty inherent in talking motion pictures has
led to the production of pictures using the native tongue in many
countries during the past year. Thus we find Turkey making a
feature in native Arabic that had a four weeks' run. In Ireland,
Louis Elliman, Ltd., will shortly present Sweet Iniscara with an all-
Irish cast. In Spain, the Compania Espanola Americana, a recently
created Spanish film company, has equipped a studio in Ciudad
Linear with Klangfilm Tobis recording and reproducing sets. An-
other company by the name of Hispanophon has been created at
Valencia to make joint Spanish-German productions. Film produc-
tion at Sievering, Austria, has benefited by the very low cost of
production. In Australia a company known as British National
Films, Ltd., has been formed to produce sound pictures in that
country. In Czechoslovakia, the Elekta Film Co. plans to cooperate
with the Gaumont F. F. A. of Paris, in order to produce sound
features in Czech, German, and French versions. In Japan about
14 per cent of the total market consists of foreign films of all sorts,
and of this amount at least 90 per cent consists of films in which
the sense of the scene is conveyed by superimposed titles in Japanese.
In the smaller cities, and in the smaller theaters of the larger cities,
the native interpreter or "benshi" is still used. The Odeon Film,
of Rome, is now working on the production of several shorts with
June, 1933]
PROGRESS COMMITTEE
497
Arabian dialog illustrating scenes of Arabian life, and intended
for distribution in Egypt, Turkey, Arabia, Syria, and Palestine.
The first Yugoslav film, called The Coast of a Thousand Islands,
showing beautiful landscapes in Dalmatia, was recently exhibited
in Belgrade. This film was made in two versions, Serbo-Croatian
and German. In Sweden, a total of 30 feature productions was made
during 1932. A large studio is being built in the vicinity of Sundy-
berg in which the recording and electric light installations will be
supplied by the Dutch Philips Company.
MOTION PICTURE THEATERS THROUGHOUT THE WORLD
Wired for Sound Silent Total
Europe
U. S. A.
Latin America
Far East
Canada
Africa and Near East
Total
17,822 12,801 30,623
14,000 5,042 19,042
1,830 3,716 5,546
2,147 2,775 4,922
777 323 1,100
379 312 691
36,955 24,969 61,924
REFERENCES
1 Internal. Phot., 4 (Sept., 1932), p. 8.
2 Internal. Phot., 5 (Feb., 1933), p. 21.
3 Phot. J. Supp., 72 (Apr., 1932), p. 5.
4 Phot. Ind., 30 (June 8, 1932), p. 578.
5 Phot. Ind., 30 (Aug. 24, 1932), p. 843.
6 Kinemat. Weekly, 182 (Apr. 28, 1932), p. 64, et seq.
7 Internal. Phot., 4 (Sept., 1932), p. 10.
8 /. Soc. Mot. Pict. Eng., XIX (July, 1932), p. 891.
9 J. Opt. Soc. Amer., 22 (Apr., 1932), p. 204; Ibid., 23 (July, 1933).
10 /. Opt. Soc. Amer., 23 (June, 1933).
11 Bur. Stand. J. of Research, 8 (Apr., 1932), p. 481; Ibid. (June, 1932), p. 711,
and 9 (Oct., 1932), p. 529.
12 Brit. Pats. 369,799; 369,592; U. S. Pat. 1,846,230.
13 U. S. Pat. 1,870,662; Brit. Pats. 364,852; 366,517; 373,004; Ger. Pat.
541,596.
14 U. S. Pats. 1,853,462; 1,861,330; 1,870,930; Brit. Pat. 371,153; Ger. Pats.
535,913; 545,486; 548,558.
15 Brit. Pat. 363,989.
16 Amer. Cinemat., 13 (Mar., 1933), p. 10; Internal. Phot., 5 (Mar., 1933), p. 8.
17 Amer. Cinemat., 12 (Apr., 1932), p. 40.
18 Amer. Cinemat., 13 (May, 1932), p. 10.
19 Kinemat. Weekly, 185 (July 14, 1932), p. 50. Also Manufacturer's Catalogues.
20 Amer. Cinemat., 13 (June, 1932), pp. 16-47; /. Soc. Mot. Pict. Eng., XX
(Jan., 1933), p. 84.
498 PROGRESS COMMITTEE [j. s. M. P. E.
21 Amer. Cinemat., 12 (Mar., 1932), p. 16; Amer. Cinemat., 12 (May, 1932),
p. 34; J. Soc. Mot. Pict. Eng., XIX (Oct., 1932), p. 329.
22 Amer. Cinemat., 12 (Mar.-May, 1932), pp. 16, 34, 37.
23 U.S. Pats. 1,849,681; 1,877,355; 1,880,393; 1,880,394; Brit. Pats. 369,833 ;
372,228; 373,950; 375,723.
24 Internal. Phot., 4 (Nov., 1932), p. 7.
25 Brit. J. of Photography, 79 (Apr. 15, 1932), p. 231.
26 Photographic J., 72 (Aug., 1932), p. 352.
27 Kinotechnik, 14 (Jan. 20, 1932), p. 26.
28 /. Soc. Mot. Pict. Eng., XIX (Dec., 1932), p. 522.
29 Amer. Cinemat., 13 (Dec., 1932), p. 34.
30 Brit. Pat. 362,885.
31 /. Soc. Mot. Pict. Eng., XVIII (Feb., 1932), p. 255.
32 Internal. Phot., 4 (Sept., 1932), p. 30.
33 Kine. Weekly, 190 (Dec. 8, 1932), p. 3.
34 U. S. Pat. 1,865,186; Fr. Pat. 703,713; Brit. Pat. 357,817.
35 Ger. Pat. 538,714.
36 Brit. Pat. 371,077.
37 Brit. Pat. 362,395.
38 Brit. Pat. 369,616; Ger. Pat. 336,402.
39 U. S. Pat. 1,871,622.
40 U. S. Pat. 1,851,166; Brit. Pats. 362,876; 371,872.
41 U. S. Pat. 1,850,220; Ger. Pats. 530,851; 540,183.
42 U.S. Pat. 1,831,771; 1,860,218.
43 U. S. Pats. 1,844,418; 1,855,198; Brit. Pat. 365,108; Ger. Pat. 539,433.
44 U. S. Pat. 1,843,595; Fr. Pat. 714,629.
45 U. S. Pats. 1,830,637; 1,849,473; Fr. Pats. 708,665; 711,794.
46 Fr. Pat. 707,511.
47 Brit. Pats. 362,490; 363,387; 363,409; 363,447; Fr. Pat. 712,519.
48 U. S. Pats. 1,833,634; 1,845,519; 1,853,683; 1,857,132; Brit. Pats. 358,643 ;
364,559; 364,627; 366,175.
49 Movie Makers, 7 (Oct., 1932), p. 457.
50 Movie Makers, 8 (Jan., 1933), p. 24.
51 Amer. Cinemat., 13 (Jan., 1933), p. 32.
52 Amer. Cinemat., 13 (Aug., 1932), p. 11.
53 Amer. Cinemat., 13 (June, 1932), p. 32.
54 Amer. Cinemat., 13 (Aug., 1932), p. 1.
55 Amat. Phot. & Cinemat., 74 (Sept. 21, 1932), p. 274.
56 Amer. Cinemat., 12 (Mar., 1932), p. 35.
87 Amer. Cinemat., 13 (June, 1932), p. 46.
58 Amer. Cinemat., 13 (Aug., 1932), p. 36.
59 /. Soc. Mot. Pict. Eng., XX (Feb., 1933), pp. 128-141.
60 /. Soc. Mot. Pict. Eng., XVIII (Feb., 1932), p. 141.
61 /. Soc. Mot. Pict. Eng., XIX (Sept., 1932), p. 219.
62 Electronics, 5 (Nov., 1932), p. 336.
63 Gen. Radio Exp. (Feb., 1933), p. 1.
64 /. Soc. Mot. Pict. Eng., XVIII (Feb., 1932), p. 172.
65 Kinemat. Weekly, 184 (June 2, 1932), p. 62.
June, 1933] PROGRESS COMMITTEE 499
66 /. Soc. Mot. Pict. Eng., XIX (Dec., 1932), p. 512.
67 Brit. Pat. 372,373.
68 Amer. Cinemat., 13 (Jan., 1933), p. 8.
69 Internal. Proj., 2 (Mar., 1932), p. 14; Technique Cinemat., 3 (Feb.,
1932), p. 69; J. Soc. Mot. Pict. Eng., XIX (Dec., 1932), p. 565.
70 U. S. Pats. 1,828,032; 1,856,541; 1,857,152; 1,857,559.
71 Technique Cinemat., 3 (Mar., 1932), p. 76; Ibid., 3 (Jan., 1932), p. 8.
72 U. S. Pats. 1,843,663; 1,850,615; 1,850,641; 1,851,705; 1,863,558; 1,864,-
445; 1,871,281; Brit. Pats. 364,009; 365,233; Fr. Pat. 710,716.
73 /. Soc. Mot. Pict. Eng., XVIII (Apr., 1932), p. 417.
74 /. Soc. Mot. Pict. Eng., XIX (Nov., 1932), p. 477.
75 /. Soc. Mot. Pict. Eng., XIX (Oct., 1932), p. 305.
76 Cinematograph Times (Feb., 1933).
77 Cinema (July 12, 1932).
78 Cinema (April 5, 1932).
79 Amer. Cinemat., 12 (Feb., 1932), p. 27.
80 Bell Tele. Quarterly, XI (Oct., 1932), p. 293.
81 /. Soc. Mot. Pict. Eng., XIX (Nov., 1932), p. 451. .
REPORT OF THE SOUND COMMITTEE*
The Sound Committee has compiled in this report an outline of the
major problems relating to sound recording and reproducing that re-
quire solution. Coordinated summaries of this sort, which necessi-
tate first a broad and unbiased survey, may prove of value by empha-
sizing the limiting factors in the several branches of the industry
whose inter-relationship is too often overlooked.
FREQUENCY EXTENSION
The recording of a wider range of frequency on sound film brings
into prominence certain problems that have heretofore been of con-
siderably less importance. With high-frequency extension, distor-
tion becomes more readily discernible, and film ground noise more
noticeable. To prevent the former, several matters require con-
sideration. Film propulsion in recording and reproducing mecha-
nisms must receive attention, particularly as regards the 96-cycle
sprocket hole effect. Overloading of any character must be more dili-
gently guarded against. Detrimental effects introduced in printing
should be recognized and corrective measures applied. While no new
requirements have been introduced in film developing and printing,
divergence from optimum conditions is more readily apparent. To
combat ground noise, it is imperative to employ all possible refine-
ments during film processing and all care in the preservation of the
release prints themselves. With low -frequency extension, a-c. hum
becomes a more important factor, and may necessitate in many cases
more effective electrical filtering.
With wider frequency range, more realistic reproduction, particu-
larly of music and sound effects, becomes a fact. The need for in-
crease in volume range becomes increasingly urgent to effect na-
turalism.
REVIEW ROOMS
Now that requirements for optimum listening conditions in audi-
toriums are fairly well known, a first effort toward standardization
* Presented at the Spring, 1933, Meeting at New York, N. Y.
500
SOUND COMMITTEE 501
of quality should be made by providing correct acoustic properties in
the producers' review rooms. A producer's who views his product in
incorrectly treated review rooms, or with equipment that is not repre-
sentative of the best theater practice, may acquire a distorted im-
pression of the sound quality that his studio is obtaining in its record-
ings. Furthermore, if the review rooms are faulty, the product itself
tends to become changed in quality, since the sound departments
will wish to make it sound well in the particular locations where the
studio executives are most apt to listen.
While there are fundamental acoustic characteristics that differen-
tiate large and small rooms which, on the basis of present knowledge,
appear to preclude the possibility of making the acoustics of review
rooms exactly simulate those of theaters, the producers can at least
see to it that bad defects are eliminated from their review rooms.
Indications are that at the present time many review rooms are too
dead and should be more reverberant, not only in order to improve
their own qualities but at the same time to make them more nearly
approximate theater conditions. Many rooms do not have the de-
sirably smooth "reverberation vs. frequency" characteristic, nor the
advocated greater amount of liveness at the low frequencies. Some
rooms have resonances that are most detrimental to proper listening
conditions. There are many precautions that should be observed
in such important places of critical judging that can best be attended
to by the engineer after surveying and analyzing each individual
room. By eliminating the acoustic deficiencies it would be possible
to judge a picture on its own merits, without the danger of attributing
to it defects inherent in the room itself, and also to obtain a better
impression of the ultimate effectiveness of the picture in the theater.
Although many theaters still remain intolerable in their acoustic
properties, the efforts of the studios should be directed toward pro-
viding a product suitable for the better houses, in the hope that the
inferior theaters may have an incentive to improve their condition.
The Sound Committee's report in the Spring of 1932 discussed broadly
the need for acoustic correction in theaters. This subject can not be
reiterated too often or too strongly.
FILM PROCESSING
Although universal standardization of film processing may not be
feasible at present, each producer should be in a position to formulate
the requirements for best results with his own films, and should de-
502 SOUND COMMITTEE [j. s. M. P. E.
mand that each reel of all release prints comply with specific require-
ments; and the film laboratories should on their part be capable of
complying with the specifications of the producing studios. Even if
these requirements should entail additional cost for the release print,
the contrary of which is more likely true, the increase would be a small
item in comparison with the total cost of the picture, and would be
well justified by assuring that no defective or inferior release prints
find their way into the theaters. Producers should bear in mind that
their incomes are derived either directly or indirectly from the customer
who pays to see and hear the release print in the theater, and not
what the producers themselves experience in their own review rooms
or in preview houses. A poor print supplied to an exhibitor, who
judges it himself or hears about it from his patrons, may create a bias
in the exhibitor's mind against the entire product of the producer who
supplied it.
SILENT CAMERA
The Academy of Motion Picture Arts and Sciences continues its
search for a truly silent camera. While the introduction of directive
pick-up devices has been of material benefit in many cases, a silent
camera is still a very real need in the studios. The Society should co-
operate with the Academy in any way possible if such assistance will
expedite a satisfactory conclusion of the work.
ECONOMIES
Effort toward decreased production costs is evidenced by econo-
mies in recording practices being employed in several Hollywood stu-
dios. Three methods are in use which briefly are :
(1) Recording sound on both sides of a 35-mm. film and then splitting the
film through the center after it has been developed. This is usually referred to as
the "split film" method.
(2) Splitting the standard film through the center prior to recording, by which
method the 17.5-mm. film is employed from the start.
(3) Selecting choice takes from the sound negative prior to its processing and
using the faulty sound track negative for printing dailies, tests, and other inci-
dental purposes. This is sometimes called the "preselection" method.
Because of differences in methods of operation in the several studios,
there seems to be no reason to standardize any particular method, as
one of the three fits nicely into the existing routines of most studios
without necessitating change.
June, 1933] SOUND COMMITTEE 503
ACOUSTICS
At the 1932 Spring Convention in Washington, the Sound Com-
mittee was asked by President Goldsmith to study the question of
studio vs. auditorium acoustics. The subject is complex, and no
quantitative relation has yet been shown to exist between the two
factors. The need of further study is indicated. The results of in-
vestigations that have been made to date have been briefly summa-
rized as follows :
Mr. A. P. Hill1 discusses the relation between reverberation times
in theaters and reverberation times in studios where recordings are
made. The treatment is abstract and mathematical, and not con-
cerned with the phenomenon of achieving proper illusion in motion
pictures. The problem is resolved into three main divisions: re-
verberation in the studio, reverberation in the set, and reverberation
in the theater when the sound source is not cut off instantaneously,
but decays at the rate existing in the recording studio. For the cases
where the theater is comparatively "live" and the recording set is
"dead," the resulting combined reverberation is not appreciably
greater than would exist in the theater alone with an instantaneously
cut off sound source. The greatest directly additive effect in re-
verberation occurs when the studio and the theater have approxi-
mately equal reverberation periods.
Reproduction of speech and music is not, however, entirely a matter
of reverberation treated mathematically as a purely physical factor;
psychological considerations play an important though illusory part.
It seems that it is necessary, for best results, to maintain a close degree
of correlation between what the ear appears to hear and the eye to see.
Thus, while we know that articulation is best when recordings are
made under highly dead conditions, the psychological impression is
most satisfactory when the effective reverberation is made to corre-
spond to that of the scene being depicted.
The question of illusion in recording is resolved by Mr. J. P. Max-
field2 into two factors : one the distance of the recording microphone
from the source, and the other the amount of reverberation existing
in the set. The two factors mentioned here may be combined into
one: the ratio of direct to reflected sound energy. On the basis of
his recording experience, Maxfield gives curves showing the relation
between the focal length of the lens used, and the placement of the
microphone for three types of sets: live, average, and dead.
Mr. R. L. Hanson at the November, 1931, meeting of the Acoustical
504 SOUND COMMITTEE
Society of America discussed the causes of the sensation of liveness.
He considers that monaural recordings are more live than would be
expected from listening binaurally at the microphone position, owing
to the fact that the intensity fluctuations resulting from the shifting
interference patterns during sustained as well as decaying sound are in
effect reduced by a binaural pick-up. The fluctuations in intensity
must, therefore, be reduced in the monaural pick-up to make the two
methods comparable in results. The employment of two micro-
phones on a single recording channel does not, of course, accomplish
this. Since the only feasible means of reducing such fluctuations is
to use sets somewhat deader than natural and closer microphone
locations than might otherwise be desired, we accept such compromise
for monaural recording.
PROGRESS
Theater reproducing equipment has remained substantially un-
changed over a period of years while studio recording has progres-
sively improved. The situation was rapidly approaching when the
studios might feel it useless to improve their product further unless
the theaters kept pace with better reproducing apparatus. For-
tunately many theaters are at the present time being provided with
equipment that accommodates a wider band of frequencies, with re-
sulting improvement in the reproduction 'of both dialog and music.
There is now a definite incentive for the studios to perfect their re-
cording still further and be prepared to accept promptly any new ad-
vances that may be imminent. The knowledge that greatly superior
sound records can be effectively reproduced by the theater equipment
is an interesting situation that has probably not heretofore existed.
H. B. SANTEE, Chairman
M. C. BATSEL C. L. LOOTENS
P. H. EVANS W. A. MACNAIR
N. M. LA PORTE W. C. MILLER
E. W. KELLOGG H. C. SILENT
S. K. WOLF
REFERENCES
1 HILL, A. P. : "Combined Reverberation Time of Electrically Coupled Rooms,"
/. Acoustical Soc. of Amer., IV (July, 1932), No. 1, Part I, p. 63.
2 MAXFIELD, J. P.: "Some Physical Factors Affecting the Illusion in Sound
Motion Pictures," /. Acoustical Soc. of Amer., HI (July, 1931), No. 1, p. 69.
REPORT OF THE COMMITTEE ON STANDARDS AND
NOMENCLATURE*
In order that the Standards Committee might be representative
of the entire industry, an effort has been made to include in its
personnel members connected with all the various branches of
motion picture engineering, in order that the points of view in mat-
ters of standardization of all these branches be brought before the
Committee; and to make the scope of the work of standardization
as broad as possible, a number of the members of the Committee
are chairmen of other committees of the S. M. P. E., which committees,
dealing with specific subjects, are in a position to propose standards
for consideration by the Standards Committee. In order to indicate
the representative nature of the membership of the Standards Com-
mittee, therefore, there is appended to this report a list of the mem-
bers, together with their commercial affiliations. In the few cases
that infrequently arise in which an interest particularly concerned
with the projects at hand is not represented on the Committee, an
effort is always made to obtain the points of view of those interests
on the subjects under consideration, either by correspondence or by
inviting their representatives to attend meetings of the Committee
as guests.
At the Washington Convention, in May, 1932, some discussion was
held regarding the method of validating S. M. P. E. standards. The
Standards Committee was requested to submit a method of procedure
to the Board of Governors for its consideration. As a result of action
by the Standards Committee, the Chairman submitted a letter to the
Board of Governors under date of May 2, 1932. This letter, to-
gether with a proposal to circularize the entire membership of the
Committee in order to obtain votes on proposals for standardization,
was submitted to the Board of Governors at the meeting of July 7.
The exact wording of the proposal submitted to the Board of Gover-
nors reads:
"It is proposed by the Committee on Standards and Nomenclature
of the Society of Motion Picture Engineers that the following pro-
cedure be adopted, in order to establish for the Society a method of
* Presented at the Spring, 1933, Meeting at New York, N. Y.
505
506 STANDARDS AND NOMENCLATURE [j. s. M. P. E.
validating and approving proposals for the standardization of motion
picture materials, equipment, technic, acceptable practice, and di-
mension, definitions, and quantities relating thereto: that an ade-
quate study of the problems at hand be made by the Committee, and
that the adequacy of this study be established (1) by the largeness of
the number of appointees to the Committee, (2) by choosing these ap-
pointees so that all important interests in the industry concerned with
the questions at hand are represented on the Committee, and (3) that
when it is difficult or impossible for all important interests of the
industry to be represented on the Committee, or whose representa-
tives can not attend the meeting of the Committee, the Standards
Committee should communicate with those interests in order to ob-
tain their opinions and arguments, before making any recommenda-
tion of standards.
"Having made such an adequate study, as outlined above, the
Committee should discuss the proposals in meeting; if necessary,
taking a tentative vote on the question at hand, in order to indicate
whatever consensus of opinion there may be. This vote, however,
should not determine the acceptance of the proposal. Final action
on the proposal should be obtained by letter ballots, returned by all
members of the Committee, to whom previously has been sent a
transcript of the proceedings of the meetings at which the questions
to be voted upon were discussed."
The Board of Governors acted upon the proposed method of vali-
dating standards and decided upon the following procedure :
"All proposals of standardization to be submitted to the Board of
Governors must first receive the recorded affirmative votes of three-
fourths of the entire Standards Committee received within thirty
days from the time the voting ballots are mailed. Upon receipt of a
report, approved in this manner by the Standards Committee, the
Board of Governors will accept or reject the report; if accepted, it will
be published in the next succeeding issue of the JOURNAL, accom-
panied by an invitation to the members of the Society to submit their
comments on the report. At a meeting of the Board of Governors,
occurring not sooner than thirty days after the publication of the re-
port, the Board may consider these comments and take final action on
the proposals, validating them as standards of the Society, or rejecting
them."
At a meeting of the Board of Governors held on October 5, 1932,
the following action was taken on the method of validating and ap-
June, 1933] STANDARDS AND NOMENCLATURE 507
proving and publishing reports and standards submitted by the
Standards Committee:
"It is moved and passed that a majority affirmative vote of letter
ballots received within thirty days on specifically stated recommenda-
tions of the Standards Committee should be authorization for early
publication of corresponding material in the JOURNAL, with an ad-
joined request for comments from all those who are interested. It
should be the duty of the office of the Society to bring all communica-
tions relative to the published recommendations to the attention of
the Board of Governors at its earliest meeting. Such recommenda-
tions, if later approved by the Board of Governors, should be repub-
lished as S. M. P. E. recommended practice."
Since the last report of the Standards Committee, the Board of
Governors has officially acted upon recommended standards for 16-
mm. sound film. The dimensional data published in the JOURNAL of
November, 1932, have therefore been approved as the official di-
mensions recommended by the Society, and these approved standards
have been submitted to the American Standards Association for con-
sideration.
As there are in foreign countries standardizing agencies interested in
the motion picture field, it is obviously desirable that there be as close
cooperation as possible between the S. M. P. E. and the foreign agen-
cies. The principal international organization interested in stand-
ards for the motion picture field is the International Congress of
Photography. Dr. Walter Clark of the Eastman Kodak Co., Chair-
man of the American National Committee, has appointed the Chair-
man of the Standards Committee of the S. M. P. E. as a member of the
American National Committee of the International Congress of
Photography. Dr. Clark has suggested that the S. M. P. E. Standards
Committee might act in a sense as a sub-committee of the American
National Committee in order to provide a channel for obtaining in-
ternational consideration of proposals for standardization. It is un-
derstood that the Secretary of the American National Committee acts
as a sort of clearing house between the committees in this country and
the corresponding committees in other countries.
There has been some direct correspondence between the Chairman
of the S. M. P. E. Standards Committee and the Chairmen of the
Standards Committees in Germany, England, and France, regarding
the interpretation of standards as published in the JOURNAL. In each
508 STANDARDS AND NOMENCLATURE [j. s. M. P. E.
case, it has been possible to clarify the interpretation of our pub-
lished data.
At the present time, there are active sub-committees dealing with
sensitometric standards and with nomenclature. Mr. L. A. Jones
is the chairman of the Sensitometric Standards Sub- Committee,
and Professor A. C. Hardy is the chairman of the Sub-Committee on
Nomenclature. Mr. Jones' sub-committee is preparing a preliminary
report outlining the progress that has been made by the International
Congress of Photography relative to sensitometric standards and
explaining the fundamental constants that are being considered as
suitable for standardization. Professor Hardy expects that his
sub-committee will have a report completed by next fall.
At the present time, the Standards Committee has under consid-
eration the following proposals, in addition to the subjects mentioned
above, which are being considered by the sub-committees.
(1) A definite proposal to eliminate the present type of negative perforation
and to use the present positive perforation for all negatives as well as positives.
(2) The revision of the Standards Booklet. All items in the booklet are be-
ing reconsidered at the present time, as some of the items are definitely in need of
revision, and it is desirable to include additional standards and recommendations.
(3) Consideration is being given to the possibility of recommending certain
standard sizes of projection screens.
(4) An attempt is being made to reach agreement on standard widths for reel
hubs for use in projection equipment.
The Standards Committee will welcome suggestions from the mem-
bership at large in regard to suitable proposals for standardization.
M. C. BATSEL, Chairman
RCA Victor Co., Inc.
W. H. CARSON, N. M. LA PORTE,
Agfa Ansco Corp. Paramount Publix Corp.
L. E. CLARK, D. MACKENZIE,
Clarco, Inc. Electrical Research Products, Inc.
L. DE FOREST, G. F. RACKETT,
De Forest Television Co. Technicolor Motion Picture Corp.
J. A. DUBRAY, W. B. RAYTON
Bell & Howell Co. Bausch & Lomb Optical Co.
P. H. EVANS, C. N. REIFSTECK,
Warner Bros. Pictures, Inc. RCA Victor Co., Inc.
R. M. EVANS, H. RUBIN,
De Luxe Laboratories, Inc. Paramount Publix Corp.
June, 1933] STANDARDS AND NOMENCLATURE 509
R. E. FARNHAM, H. B. SANTEE,
General Electric Co. Electrical Research Products, Inc.
C. L. FARRAND, V. B. SEASE,
United Research Corp. Du Pont Film Mfg. Corp.
H. GRIFFIN, T. E. SHEA,
International Projector Corp. Bell Telephone Laboratories, Inc.
A. C. HARDY, J. L. SPENCE,
Mass. Institute of Technology. Akeley Camera, Inc.
R. C. HUBBARD, E. I. SPONABLE,
Consolidated Film Industries, Inc. Fox Film Corp.
L. A. JONES, S. K. WOLF,
Eastman Kodak Co. Electrical Research Products, Inc.
DISCUSSION
MR. COFFMAN: From the point of view of the laboratory, the entire problem
of control of not only printer slippage but the location of the sound track as well,
is rather intimately connected with the change of perforation that is being
proposed by the Committee. Such a change will have a great effect on the life
of the negatives, for definite evidence is available that shows that the old negative
perforation is much more subject to wear and tear in the process of printing
than the present positive perforation.
REPORT OF THE PROJECTION SCREENS COMMITTEE*
Since its last report, the Projection Screens Committee has engaged
in studies of several matters pertaining to screens and projection
practices, the most important of which are : standardization of sizes
of manufactured screens, a simple method of determining reflectiv-
ity of the screen in the theater, and sound transmission character-
istics of screens in connection with the extension of the range of
frequency of reproduced sound. These, with other matters of
interest, are discussed in the following sections.
SCREEN SIZES
The Committee has been considering the possibility of standardiz-
ing screen sizes ever since it was organized. There are several reasons
for standardization. According to manufacturers, the foremost
advantage will be the elimination of errors arising in ordering and
assembling screens. There is also the possibility of economy due to
the fact that the process of assembling screens according to standard
specifications may be resolved into a standard procedure. Another
advantage is the inherent convenience of standards, as contrasted
with haphazard, chaotic conditions. With these thoughts in mind,
the Committee has prepared a list of screen sizes that appears to ful-
fill the requirements of simplicity and generality of application.
It will be noted that the key number designating the screen is made
to correspond to the width of the picture. It is believed that the pic-
ture width, as a more fundamental quantity, represents a more appro-
priate selection for designating screen sizes than either the full screen
width or the width of the frame. This also accords with the proce-
dure for determining projection lenses. The full width of the screen,
including the borders, will be about 5 inches greater, and the inside
frame width an additional 8 or 10 inches, where the screen is laced to
hook on the inside. In the event that a given screen has a picture
width intermediate between two of the proposed standard sizes, the
screen to be chosen shall be the larger size, if possible. In some cases,
this might be desirable from the point of view of the audience, even
* Presented at the Spring, 1933, Meeting at New York, N. Y.
510
PROJECTION SCREENS COMMITTEE 511
though it might necessitate alteration of the supporting structure.
It is felt that a one-foot separation between sizes is small enough for
most practical purposes, besides being convenient. The following
table shows the proposed standards :
TABLE I
Proposed Standard Screen Sizes
Size Number Picture Width, Picture Height,
of Screen Feet Feet Inches
8 8 60
9 9 69
10 10 76
11 11 83
12 12 90
13 13 99
14 14 10 6
15 15 11 3
16 16 12 0
17 17 12 9
18 18 13 6
19 19 14 3
20 20 15 0
21 21 15 9
22 22 16 6
23 23 17 3
24 24 18 0
25 25 18 9
26 26 19 6
27 27 20 3
28 28 21 0
29 29 21 9
30 30 22 6
31 31 23 3
32 32 24 0
33 33 24 9
34 34 25 6
35 35 26 3
36 36 27 0
37 37 27 9
38 38 28 6
39 39 29 3
40 40 30 0
The proportion of width to height has been chosen as 4 to 3. For a
projection angle of 18 degrees, which represents an average condition,
512 PROJECTION SCREENS COMMITTEE [j. S. M. P. E.
this ratio will require a minimum amount of masking on the basis of
the new standard aperture. For other angles, more masking will be
necessary. If, however, a 4Vs to 3 screen ratio were standardized, it
would be theoretically correct for horizontal projection only, and
would require an increasing amount of masking and a correspondingly
greater amount of unused screen surface. The 4 to 3 ratio has
the further advantage that a large number of existing frames are
made to accommodate screens of such shape. Another advantage is
the simplicity of the ratio and the ease of computing heights from
widths.
It was thought that after standardizing on sizes, manufacturers
would be required to stock only a relatively small number of screens.
The Committee is informed, however, that this would be impracti-
cable inasmuch as deterioration would soon set in. For this reason, it
has been customary to make screens to order.
The Committee also recommends that the standard spacing of
grommets be 6 inches, with 12 inches as a possible sub-standard.
Some frames are designed for a 12-inch spacing, but these will also
accommodate the primary standard. The smaller spacing permits a
more even distribution of tension, which is especially desirable at the
top of the screen. When assembling a screen, the first grommets
should be placed in the center of each side and the process then ex-
tended to the edges. The screen, when mounted, should not be
stretched too tightly, but some slack should be allowed to exist to
compensate for changes produced by atmospheric conditions.
SCREEN IMAGE DISTORTION
The discussion incidental to the adoption of the new standard
aperture has helped to focus attention on the problem of screen image
distortion. Such distortion involves three elements: the projection
angle, the observation angle, and the size of the screen. Indirectly
involved is the distortion occasioned in photographing or viewing the
original scene. Masking a projected picture will avoid keystoning at
the edges ; but, of course, it will not improve the distortion within the
image itself. A thorough exposition of these factors, with an estimate
of their seriousness, would be an important contribution to motion
picture engineering. The Committee therefore proposed to one of
its members that he undertake the preparation of a paper on the sub-
ject. Mr. C. Tuttle, of the Eastman Kodak Co., kindly consented to
B. REFLECTION FACTOR - 0.43
DIRECTIONS FOR DETERMINING SCREEN REFLECTIVITY
(1) Remove these four pages from the Journal and phi them to the projection
screen, the plain sides facing the audience. They should be arranged as shown
below, hi the order B, D, F, H, leaving a distance of about six inches between
each sheet.
E
(2) The screen should next be illuminated, either by light from the projector
or by general auditorium illumination. A portion of the screen that is uniformly
clean should be chosen, and the illumination of that portion should be fairly
uniform.
(3) From a distance sufficiently great that the perforations of the screen can
not be distinguished (at least twenty feet from the screen), compare the bright-
ness of the screen with the brightness of the paper samples. Usually, the re-
flectivity of the screen will lie between the reflectivities of two of the samples;
occasionally it will approximate very closely the brightness of one of the samples.
When the screen is brighter than H it is hi excellent condition; when it is duller
than B it is unsatisfactory. For convenience in transmitting the data to the
Committee, the reflectivity of the screen should be graded according to the
letters in the diagram above. For example, if the reflectivity of the screen
should lie between the reflectivities of samples B and D, the reflectivity of the
screen should be graded as C; if the reflectivity of the screen approximates
very closely that of sample D, then it should be graded as D; and so on.
(4) This simple comparison method should be applied only to screens of the
diffusive (flat white) type, and then should be made by viewing the screen at
several angles within a range of 40 degrees from the normal to the screen. A
special technic is required for beaded and metallic screens.
(5) The Projection Screens Committee would like to be informed of the re-
sults of measurements made with these samples. Please address the Chairman
of the Projection Screens Committee, at the General Office of the Society of
Motion Picture Engineers, 33 West 42nd St., New York, N. Y., giving the fol-
lowing information: trade name of screen, name of manufacturer, age of screen,
how long ago the screen was last resurfaced, a statement of the general condition
of the screen, and the kind of ventilating system used hi the theater.
Report of the Projection Screens Committee, Journal of the Society of Motion
Picture Engineers, XX, No. 6, June, 1933.
D. REFLECTION FACTOR - 0.52
Report of the Projection Screens Committee, Journal of the Society of Motion
Picture Engineers, XX, No. 6, June, 1933.
D
F. REFLECTION FACTOR - 0.60
Report of the Projection Screens Committee, Journal of the Society of Motion
Picture Engineers, XX, No. 6, June, 1933.
H. REFLECTION FACTOR = 0.78
Report of the Projection Screens Committee, Journal of the Society of Motion
Picture Engineers, XX, No. 6, June, 1933.
H
June, 1933] PROJECTION SCREENS COMMITTEE 513
do this and prepared a paper on the subject for presentation at the
Spring Meeting of the Society.*
DETERMINATION OF SCREEN REFLECTIVITY
The Committee has been seeking for some time a simple, practical
method for exhibitors to determine the reflectivity of their screens.
The most feasible method at the present time appears to be a direct
comparison of the screen with samples of paper having known reflec-
tion values. The brightness of each sample is compared with the
brightness of the screen ; the reflectivity is determined from the sam-
ple whose brightness most nearly matches that of the screen, the
several samples being calibrated in terms of reflectivity. The in-
formation so obtained, while not strictly accurate, is reliable enough to
give the exhibitor, in a simple manner, the information he needs. It
can serve either as assurance that all is well, or as a warning that his
screen should be resurfaced or replaced in order to avoid excessive
waste of light. With screens of the beaded and diffusive type, this
simple comparison principle will not be very satisfactory because of
the specular nature of the reflection.
To illustrate the method, there are incorporated in this report four
samples of paper having the following graded reflectivities : 0.78, 0.60,
0.52, and 0.43. The values chosen were determined partly by the
availability of the paper stock and partly with the thought of achiev-
ing a scale on the basis of which a screen might be called good, fair,
poor, or unsatisfactory.
SCREEN BRIGHTNESS
The proceedings of the "Commission International de L'Eclairage,"
eighth session, published in Cambridge, England, were recently
brought to the attention of the Committee. These proceedings con-
tain reports of German and Japanese sub-committees on theater illu-
mination which should be of interest to American motion picture engi-
neers.
The Japanese sub-committee recommended that the general illu-
mination of the theater be not less than the amount required for read-
ing programs printed in 8-point type. The value proposed in com-
pliance with this requirement is about 0.18 foot-candle. This com-
pares with 0.1 foot-candle found by the S. M. P. E. Theater Lighting
* ''Image Distortion in the Projection and Viewing of Motion Pictures," pre-
sented at the Spring, 1933, Meeting at New York, N. Y., and to be published in
the JOURNAL in the near future.
514 PROJECTION SCREENS COMMITTEE [j. s. M. P. E.
Committee1 in 1931 to be adequate for locating seats easily after the
eyes of the patron had accommodated themselves to that level of
illumination. With the auditorium light at 0.18 foot-candle, the
Japanese found that a screen illumination of 9.3 foot-candles was
sufficient to preserve picture contrasts, with higher values not ob-
jectionable. This finding included the observation that care had to
be exercised to prevent auditorium light sources from illuminating
the screen directly and from shining into the observers' eyes.
According to the report, measurements made in eleven of the prin-
cipal theaters of Tokyo showed screen illumination varying from 3.1
to 9.8 foot-candles, without film and shutter. The average was 6.35
foot-candles, considerably below the recommended value. In com-
paring these values with measurements made in America, it must be
remembered to differentiate them from those of our measurements
made with the shutter running. Shutters reduce the average bright-
ness by 50 per cent, although the brightness during the illuminated
intervals remains unchanged. The reflectivities of the screens were
comparable with those of American types of screens.
The German sub-committee reported that it is not customary in
their country to provide any general illumination other than that fur-
nished by reflection of projected light from the screen. Screen illu-
mination measured in ten theaters varied from 6 to 16.8 foot-candles
at the screen centers, presumably without film, shutter condition not
mentioned. The corresponding values for screen brightness ranged
from 2.61 to 9.6 foot-lamberts.
PERFORATIONS IN SCREENS
The acoustic transmission characteristics of screens are being re-
examined, relative to recent developments on extended recording and
reproduction frequency ranges. Difficulties are anticipated for only
the higher frequencies. When the Committee first reported on the
subject of screen transmission, it included the statement that screens
that are satisfactory up to 6000 cycles are usually found to attenuate
less than 4 db. at 10,000 cycles. Inasmuch as this value does not
represent excessive attenuation, and since lesser amounts would be
difficult or impracticable to obtain with commercial screens, the
Committee feels that it can recommend it as representative of good
practice. Some screens hitherto adjudged satisfactory will not be
altogether acceptable for use with reproducing systems of wide fre-
quency range.
June, 1933] PROJECTION SCREENS COMMITTEE 515
There has been considerable discussion as to the advisability of de-
vising some means of eliminating the necessity for perforations in
screens. Both sound transmission tests and acoustic theory indicate
the necessity for perforations. Recently, tests were made at the Bell
Telephone Laboratories of a series of screens identical in all respects
except as regards the number of perforations. One screen, with-
out any perforations whatsoever, showed excessively large attenua-
tion, especially at high frequencies. The others, with graded amounts
of open area, showed increasing efficiency of sound transmission.
Since it is thus evident that perforations are necessary when the
loud speakers are placed directly behind the screen, the question
arises as to whether it would be possible to place the loud speakers to
one side of the screen. In the past, this method has been tried and
apparently found wanting, inasmuch as the practice has been dis-
continued. One difficulty was loss of illusion; another was that the
method lacked the mechanical simplicity and flexibility inherent in
"flying" the speakers, or mounting them on towers behind the screen
so that they could be removed at will. The present standard method
seems to meet most operating demands comparatively satisfactorily,
although it also has its disadvantages.
One objection to the perforations is the loss of screen brightness
that they cause : 5.8 to 8.5 per cent, depending upon the make of the
screen. This loss is, of course, undesirable, especially when the avail-
able illumination is already scant. Another objection sometimes
offered is that the perforations may be visible from the auditorium
and thus mar the appearance of the projected picture. However,
when the limiting distance for the visibility of the holes is computed
from their diameter and the known resolving power of the eye, it
appears that this consideration will be usually unimportant. A large
value for the diameter of the perforations is 0.0625 inch; the resolving
power of the eye may be taken as 1 part in 3438. 2 The limiting dis-
tance at which the perforations are just discernible is, therefore, 18
feet. Many makes of screens have perforations of smaller diameter
which are, therefore, visible only within correspondingly shorter dis-
tances.
S. K. WOLF, Chairman
E. R. GEIB A. L. RAVEN
H. GRIFFIN R. T. RASMUSSEN
J. H. KURLANDER H. RUBIN
W. F. LITTLE C. TUTTLE
516 PROJECTION SCREENS COMMITTEE
REFERENCES
1 "Report of Theater Lighting Committee," /. Soc. Mot. Pict. Eng., XVI
(Feb., 1931), No. 2, p. 239.
2 HARDY, A. C., AND PERRIN, F. H.: "The Principles of Optics," McGraw-Hill
Book Co., New York, 1932, p. 190.
DISCUSSION
MR. RICHARDSON: Perforations in screens vary in number from 25 to 40 per
square inch; and they also vary in size. If screens are to be perforated at all
they should all have the same number of perforations to the square inch, and all
perforations should be of the same diameter.
As for testing screens, I have suggested many times that when exhibitors
purchase new screens they should also obtain a sample of the material that can
be stored in a dry dark place, wrapped in black cloth, so that at any time the
surface of the screen may be compared with that of the carefully preserved sample.
The proposed plan of using differently colored samples of paper for comparison
appears to be good, but the paper must be carefully selected so that it does not
become discolored with time ; and exhibitors must be warned to keep the samples
wrapped in black cloth and in a dry dark place. However, if the screen be tinted
as many screen surfaces are, comparison with paper samples will hardly serve.
MR. LITTLE: Paper samples entirely devoid of color would, of course, be
preferable. However, with a little practice brightness matches can be made quite
accurately. The problem of keeping the paper samples clean is not difficult,
i. e., they may be kept within the pages of the book. If they become soiled or
discolored, new samples may be obtained; or if in the JOURNAL, by repeating the
issuance from time to time, the exhibitors will always have clean sheets of paper
available. It is hoped that some of the screen manufacturers will see the value
of such sheets and will themselves arrange for their distribution.
MR. RICHARDSON: But does not paper contain chemicals that cause it to be-
come discolored?
MR. LITTLE: The discoloration or change of reflection factor of the samples
due to aging is as a rule very small. Samples in our possession have remained
constant within 2 or 3 per cent for a period of at least ten years.
REPORT OF THE STUDIO LIGHTING COMMITTEE
Owing to the wide dispersion of the members of the Studio Lighting
Committee the report of the Committee has this year been compiled
from information obtained from the various manufacturers of equip-
ment regarding developments in light sources, and the heads of elec-
trical departments in the various studios as regards current practice
and operation.
ARC CARBONS
The manufacturers of arc carbons have carried on extensive de-
velopmental work in producing carbons suitable for illumination in
connection with the production of colored motion pictures. A new
automatic arc mechanism that will comply with the requirements of
present studio operation is undergoing development; and although
the work has not yet reached the stage at which a complete report is
available, the manufacturers are much encouraged over the results
that have been obtained.
The arc carbons that have been developed for the new mechanism
are of small diameter and have been designed to produce a flaming arc
of high intensity.
VAPOR LAMPS
The manufacturers of vapor lamp equipment have produced sodium
arc tubes that are claimed to have three to four times the luminous
efficiency of incandescent lamps of corresponding wattage rating, and
while the investigations of this Committee do not reveal any apparent
practical application of the sodium arc to studio lighting, yet it seems
advisable that the new developments in this kind of vapor lighting
should be mentioned in the report. At present the spectral character-
istics of this arc do not accord with the film sensitivity, but modifica-
tions of- either the illuminant or the film stock might in the future
cause the sodium arc to be of use in the motion picture industry.
INCANDESCENT LAMPS
The development of bi-post construction for high- wattage lamps has
been an outstanding contribution by the manufacturers of filament
* Presented at the Spring, 1933, Meeting at New York, N. Y.
517
518 STUDIO LIGHTING COMMITTEE [j. s. M. P. E.
lamps. Referring to Fig. 1, it will be noted that the new bi-post
construction changes the basing of the lamp so as to eliminate the
cemented prong base that has heretofore been supplied by the various
manufacturers. The new design permits adherence to much closer
manufacturing tolerances in constructing the lamp than previously,
and combines all the advantageous features of previous develop-
ments with numerous other features that contribute to its ruggedness
and longer life.
The success of the small photoflood lamp has encouraged manufac-
FIG. 1. Showing the new bi-post construction for high- wattage incandescent
lamps; also the new adapter for the 5-kw., bi-post lamp.
turers toward the development of similar lamps of higher wattage.
High-intensity lamps of this type consuming approximately 1500
watts, have been tried out and have provided a luminous efficiency of
34 lumens per watt, which is about the same efficiency as that of the
photoflood lamp. The availability of such super-photoflood lamps
would be of advantage to the studio lighting technicians in solving
some of their difficult illumination problems.
STUDIO PRACTICE AND OPERATION
There has been no great change in the past year in the lighting prac-
tice of the studios. The use of the super-speed film has considerably
reduced the intensity of lighting required for exposures, has resulted
June, 1933] STUDIO LIGHTING COMMITTEE 519
in a decrease of wattage, and has greatly enhanced the photographic
results. The super-speed film required the elimination of spill-light
from the back-lighting units, and thus caused the introduction of
spill rings for masking off the unprojected light of the reflector units.
The improvement of sound recording technic has obviated some of
the restrictions heretofore imposed upon the use of arcs. Where
scenes require sharp shadows or strong contrast, and where large
night sets are being photographed, the carbon arc forms a source of
illumination that has not been excelled by any other source. The
introduction of the 5-kw., bi-post incandescent lamp has altered the
standard heretofore followed as regards bases for this size of globe.
FIG. 2. A 4-hole plugging box, 3-wire connected for
eight low-power units or four 5-kw. units.
In days when every item of expense is frowned upon, it is necessary
to provide a simple means of adapting the new lamps to the existing
equipment, and to bridge over the transition from the old design to
the new. To meet this situation, one of the equipment manufacturers
has developed a simple adapter, shown in Fig. 1, which permits the
5-kw., bi-post lamp to be used in existing equipment of all types.
The past year has seen some improvements in current distribution
facilities on motion picture stages. A number of stages have been
equipped with remote control switchboards mounted on the overhead
runways, to which are permanently connected distribution networks
of cables terminating in lightweight 4-hole plugging boxes. It is
520 STUDIO LIGHTING COMMITTEE
standard practice in the studios to equip incandescent lighting appa-
ratus with what are called "inkie" plugs; these plugs having half the
thickness of the standard stage plugs, thus permitting two plugs per
hole in the standard stage receptacle. The 4-hole plugging box illus-
trated in Fig. 2 is 3-wire connected, and allows the use of eight low-
wattage units or four units of 5-kw. capacity each. In studios that
have been employing this system, very considerable savings have
been made owing to the reduction of the time required for the rigging
and striking of lighting equipment on sets.
The low ebb of production activity during this period of economic
retrenchment has somewhat limited the development of new types of
equipment. No new equipment has been forthcoming that has had
any major effect upon general lighting practice.
P. MOLE, Chairman
L. J. BUTTOLPH C. W. HANDLE Y
R. E. FARNHAM J. H. KURLANDER
W. J. QUINLAN
REPORT OF THE PROJECTION THEORY
COMMITTEE*
Under the present organization of the Society, there are three pro-
jection committees: namely, the Projection Screens Committee,
the Projection Practice Committee, and the Projection Theory Com-
mittee. Since it is the primary function of the Projection Theory
Committee to deal with the optical principles involved in the pro-
jection of motion pictures, the work of this Committee does not lend
itself to the usual type of progress report. The optical principles
have long been established — so long, in fact, that they are seldom dis-
cussed in the current literature. Instead, one must look for them in
advanced works on optics, which ordinarily contain so much irrelevant
material that a full understanding of the theory of optical projection
is not easily acquired. The Projection Theory Committee feels
that it can be of greatest service to the Society by preparing a short
monograph on the theory of projection. This monograph will discuss
the function of the light source, the condenser, and the projection
lens; will analyze the requirements that must be met if these units
are to work together effectively; and will indicate, by a discussion
of the photometry of optical instruments, the method of obtaining
the maximum illumination of the screen with a given source of light.
As this report is written, the monograph is in outline form, and will
undoubtedly be completed during the coming summer.
Many of the problems involved in the projection of motion pictures
require careful coordination of theory and practice. During the past
year an attempt has been made to achieve this coordination through
the collaboration of the chairmen of the three projection committees.
Although this arrangement has been very successful, it involves much
wasted effort. It is felt, therefore, that with the reorganization of
committees at the time of the next election of officers, it would be well
to combine the three committees into a single projection committee.
This committee might well have a large membership, to permit di-
vision into sub-committees to deal with specific problems. This
plan would obviate the necessity of dividing the problems arbitrarily
* Presented at the Spring, 1933, Meeting at New York, N. Y.
521
522 PROJECTION THEORY COMMITTEE
into those that are primarily theoretical, those that are primarily
practical, and those that pertain primarily to motion picture screens.
A. C. HARDY, Chairman
R. E. FARNHAM W. F. LITTLE
H. P. GAGE W. B. RAYTON
C. TUTTLE
DISCUSSION
MR. F. H. RICHARDSON: Has the Committee investigated the losses that
occur in projector optical systems, including the loss at the spot and that due to
the rotating shutter?
MR. A. C. HARDY: The Committee hopes to discuss that subject in its next
report.
REPORT OF THE COMMITTEE ON THE PRESERVATION
OF FILM*
This Committee was appointed for the purpose of collecting data
and information pertaining to the preservation of all types of film
such as might be produced by the motion picture industry; but, par-
ticularly, to collaborate with the supervising architects of the new
Government Archives Building which is in course of construction
under the direction of the Treasury Department of the United
States.
Two formal meetings of the Committee were held during 1932:
one in New York, held on April 15, at the offices of the Motion Pic-
ture Producers and Distributors of America, Inc., and one at Washing-
ton, D. C., on September 12, in the office of Mr. Raymond Evans,
chief of the Office of Motion Pictures of the U. S. Department of
Agriculture.
At the latter meeting we were fortunate in having present repre-
sentatives of the office of the Supervising Architect, as well as repre-
sentatives of various branches of the government that might be
affected by any recommendations made by this Committee, and
which, under the present understanding of the plan for film preserva-
tion, might have more or less film to be turned over to the Archives.
These representatives were: Louis A. Simon, of the Office of the
Supervising Architect, Treasury Department; Lt. Com. R. A. Hyde,
of the Navy Department; Capt. F. W. Hoorn, of the U. S. Signal
Corps; Mr. A. E. Kimberly, Research Associate, Bureau of Stand-
ards, Department of Commerce; and Mr. C. J. North, of the De-
partment of Commerce.
Subsequent discussion, by correspondence and at a meeting held
during the Spring, 1933, Convention at New York, N. Y., of the
terms of the report as originally drafted led to the final report as
here presented.
This report in addition to being submitted to the Society as the
annual report of the Committee, will be forwarded to the supervising
architect's Office of the Treasury Department as containing the
Committee's recommendations to date on the problems at hand.
* Presented at the Spring, 1933, Meeting at New York, N. Y.
523
524 PRESERVATION OF FILM COMMITTEE [j. s. M. P. E.
The first approach of the Committee to this problem indicated
immediately a lack of definite understanding as to the scope of the
recommendations to be made. It was, therefore, the consensus of
the Committee that the members discuss the problem among them-
selves from the broadest possible application; and Mr. Milliken,
who is familiar with the plans of Mr. Will Hays — who has been
directly in contact with President Hoover in this matter — outlined
to the Committee his understanding of the general situation.
At the time of the earlier meeting of the Committee, it was not
possible to obtain definite information as to the space available
for storing film; and it seemed necessary, therefore, that at some
future date, a committee from the government definitely select
from the available material that which should be stored, according
to the amount of space ultimately allotted for the purpose.
At the second meeting the Committee was informed by Mr. Simon
that, under the terms of the bill that had authorized the construc-
tion of the Archives Building, there was some question as to whether
film other than that now in the possession of the governmental
departments, or in the future produced by them, would be included
among the archives, although he expressed the wish that the Com-
mittee present the question of providing additional space to accom-
modate other classes of film that might be recommended, if it were
found practicable. The Committee, therefore, discussed the form
and required capacity of such vaults as would be required, and arrived
at the following conclusions :
Air Conditioning. — It is recommended that provision be made in
the vaults for air conditioning equipment so as to maintain a tem-
perature of approximately 60°F., and a relative humidity of 60 per
cent.
(Early recommendations suggested a temperature of 40 ° to 50 ° and a relative
humidity of 60 per cent. However, it was pointed out that film stored under
climatic conditions as encountered in Washington would absorb moisture when
brought into rooms subject to ordinary atmospheric conditions, and that it would
be necessary to construct in connection with the vaults some sort of a tempering
room in which the outside temperature that the film would encounter would be
maintained at a very low humidity until the temperature of the film itself had
been raised to normal room temperature.)
The following chart was submitted by Mr. H. T. Cowling, showing
a record of temperature changes in the City of Washington over the
past 33 years :
June, 1933] PRESERVATION OF FlLM COMMITTEE 525
Absolute
Temperature
Average
Temperature
Relative
Humidity
Low
High
Mean
Min.
Max.
8A.M.
8 P.M.
14
76
33.7
25.7
41.2
67
76
Jan.
15
78
34.7
26.6
43.0
63
73
Feb.
4
93
42.6
33.8
51.4
61
74
March
22
95
53.4
43.3
63.0
58
69
April
33
96
64.2
53.9
74.1
58
73
May
43
102
72.4
62.9
82.2
70
76
June
52
103
76.8
67.6
86.4
71
79
July
49
106
74.4
65.7
83.8
74
80
Aug.
36
104
68.0
58.9
77.8
76
81
Sept.
26
92
56.9
46.9
66.3
72
81
Oct.
12
80
45.2
36.6
53.8
66
77
Nov.
13
73
36.1
28.4
44.0
66
76
Dec.
Annual
54.9 45.9 63.9 68 76 Average J
In order to facilitate the maintenance of uniform atmospheric
conditions, it was recommended that the vaults be placed below
ground, and that they be so vented as to maintain a pressure above
the outside pressure at all times. This would lead to a movement of
the air toward the outside, and would avoid condensation within the
vaults due to seasonal changes of temperature.
The next question concerned the best manner of preserving film
under all the conditions to which it would be subjected, including
the personal influences. First of all, the film as submitted for storage
in the Archives Building should be tested to determine its condition
as regards freedom from injurious chemicals due to faulty or careless
processing; and, if found to be faulty in this respect, it should im-
mediately be subjected to approved methods of rewashing and test-
ing. It was pointed out that this could be done by any of the well-
equipped laboratories in Washington, and that facilities for so doing
need not be considered as part of the equipment of the Archives Build-
ing. Although no definite recommendations were made as to the de-
tails of such a test, attention was called to an outline of these details
published previously in the JOURNAL.1'2 It was agreed by the
Committee that any of the recommended practices for the cleaning of
film should prove satisfactory to meet the circumstances.
Film Containers. — It is recommended that the film for permanent
storage be enclosed in a container made of non-corroding metal or
fiber board. It was pointed out that it was advisable that these
films should not be hermetically sealed, as this would prevent the
escape of any decomposition products or solvent contained within the
526 PRESERVATION OF FILM COMMITTEE [j. s. M. p. E.
film itself. These containers could be especially constructed to
accommodate rolls 1000 feet long or any greater convenient length.
Film Cabinets. — Within a vault conforming to the existing regula-
tions of the Fire Underwriters, except as regards its capacity, which
the Committee considers could be two or three times that of the
maximum allotted space of 750 cubic feet, provided that the total
weight of film within the vault does not exceed that permitted by the
Underwriters (10,000 Ibs.), should be built a series of cabinets con-
sisting essentially of racks or shelves made of some non-inflammable
and non-conducting material such as impregnated wood or sheet
asbestos. Each shelf should contain one unit reel, and the film
should be stored at all times in such a manner that the roll is flat,
thus avoiding uneven pressure within the roll on account of its own
weight. The roll of film should be wrapped in chemically inert
fluffless paper, and placed in an unsealed container of non-corroding
metal, or fiber board. The shelves of the cabinet should be ap-
preciably longer than the width of the film roll, and closed at the
front end either by a common door or individual doors. At the other
end, a space should be allowed between the edges of the shelves and
back wall of the cabinet, so as to provide an air chamber through the
entire cabinet which, in turn, should be connected to the outside air
by means of a vent having a capacity as recommended under the
existing regulations of the Fire Underwriters. This arrangement
will assure a minimum loss of film in the event of fire within the
cabinet.
Water Sprinkler Equipment. — There is considerable question, be-
cause of the comparatively recent development of nitrocellulose as a
supporting base for photographic film, as to the danger of fire arising
from spontaneous combustion; and vaults constructed as recom-
mended, and maintained at the proper temperature and humidity
as mentioned before, would largely eliminate danger from internal
fire. The only other point to be guarded against, therefore, involves
the possibility that the attendant may permit some condition to
arise, either within the system or from without, that might lead to
fire. In discussing the matter of the preservation of film, it is just
as important that the film be guarded against damage by water or
any other physical agent as to guard it from fire; and, if, in at-
tempting to safeguard the film from fire it be subjected to damage
by water, the end desired will not be accomplished. The Committee,
therefore, recommends that some thought be given to the danger
June, 1933] PRESERVATION OF FlLM COMMITTEE 527
inherent in the use of sprinkler heads in film vaults designed for stor-
age of valuable negatives. Unless some adequate measures be
adopted for carrying off the water, so as to prevent it from accumulat-
ing, it is felt that sprinkler heads would be a menace to the film.
While considering this matter, the Committee inspected the
vaults belonging to the Signal Corps at the War College, and those
belonging to the Department of Commerce in the new Commerce
Building in Washington, and the following conclusions were reached
in the cases of these two vaults:
Signal Corps Laboratory. — The arrangement and general construc-
tion of the vault were approved by the Committee, but the use of
sprinkler heads at the top of each vault without provision for scuppers
or other means of allowing the water to run off constituted a hazard.
Commerce Department Vault. — The vault as constructed is subject
to all sorts of outside influences, both human and atmospheric, so
that it is necessary to protect the film against fire in small unit quanti-
ties. The cabinets, made especially for this purpose for the Depart-
ment of Commerce, are adjudged to be fully satisfactory for the pur-
pose they serve; but it is felt that they represent unnecessary ex-
pense and occupy too much space for the storing of film under the
anticipated controlled conditions that will prevail in the Archives
Building. Furthermore, they require that the can of film stand
vertically, a feature against which the Committee strongly
advises.
The Arrangement and Availability of Archives Film. — For main-
taining in a usable condition all motion picture film to be preserved,
it is advisable so to arrange the handling of the film that it will be
disturbed as infrequently as possible. It is, therefore, the recommen-
dation of the Committee that upon receiving a film on any subject
from any Department of the government or other source, if this
film be in the form of a negative, a master positive and duplicate
negative be made from it immediately, to be stored separately from
the original film as a file copy and to be used for making subsequent
prints as desired without disturbing the original negative. In case
the film received is a positive, then two duplicate negatives should be
made, one to be placed permanently in storage, the other, as de-
scribed above.
Sixteen-millimeter copies should be made by reduction from each
of the 35-mm. films in the Archives, and made available for cur-
rent purposes of projection as required; subsequent 16-mm. file
528 PRESERVATION OF FILM COMMITTEE [j. S. M. P. E.
copies to be made from the duplicate negative as shall be found neces-
sary.
Periodic inspection of the original negative copies should be made
at long intervals, to determine the condition of each individual film:
by long intervals is meant a period of not less than one year or more
than five years. Each film should be carefully inspected at the end
of each interval in order to determine whether the film base is show-
ing signs of deterioration, or whether the emulsion is adhering to
the base. Measurements should also be made to determine the
amount of shrinkage that has taken place. If it is found on inspec-
tion that the film is showing marked shrinkage, which would tend,
if continued, to make it impossible to make prints from it, a new
master positive should be made at once so that the pictures con-
tained on the film shall at all times be available for future use.
Conclusion. — There are numerous factors having a direct bearing
on the preservation of film that have not been discussed by this
Committee, such as the possibility of transferring pictures to some
medium, other than nitrocellulose film, of whose permanency we are
certain, such as copper or noncorrosive metals.
As yet no study has been made of methods of storing film in other
countries, where archives are already in existence. It is the intent
of this Committee to continue its study until all matters of this kind
have been fully investigated.
Mr. Simon expressed his satisfaction at the work of the Committee,
and requested the privilege of seeking the services of this Committee
and its members at any future time that further questions might
arise in connection with the construction of the Archives Building.
W. H. CARSON, Chairman
H. T. COWLING R. EVANS J. M. JOY
J. I. CRABTREE C. L. GREGORY T. RAMSAYE
A. S. DICKINSON V. B. SEASE
REFERENCES
1 CRABTREE, J. I., AND Ross, J. F.: "A Method of Testing for the Presence of
Sodium Thiosulfate in Motion Picture Films," /. Soc. Mot. Pict. Eng., XIV
(Apr., 1930), No. 4, p. 419.
2 CRABTREE, J. I., AND IVES, C. E.: "The Storage of Valuable Motion Picture
Film," /. Soc. Mot. Pict. Eng., XV (Sept., 1930), No. 3, p. 289.
June, 1933] PRESERVATION OF FlLM COMMITTEE 529
REPORT ON METHOD USED BY THE GERMAN GOVERNMENT FOR STORING
MOTION PICTURE FILM
The following is a contribution to the report of the Committee on the Preservation
of Film by Mr. Erich Ewarth of Berlin, made at the instance of Mr. J. M. Joy, a
member of the Committee.
New methods of storing film have not yet been developed. I visited the patent
office several times without any success in finding anything, and my searches in
the libraries have also been in vain.
I wrote to and visited the Reichsarchiv (the archives, or record office of the
Reichsarchiv) at Potsdam, where are stored all important films, positive and
negative. The storehouse itself is rather simple; formerly a small brick stable,
it has been adapted for the new purpose by the installation of iron and wooden
shelves.
I had a long talk with the head of the film department, and Senior Councillor
Ruppert, who told me that the Chemische Technische Versuchsanstalt (laboratory
for chemical technical research) of the government had been asked to recommend
the best and most scientific method of storing films.
The information was received that such a method did not exist. However, the
stable was rebuilt, and the films are now being kept in the following manner:
Each film roll is put into a cardboard box made of waterproof "Vulcopa"
(a fiber-like material) ; into the box is laid a piece of camphor (about 3X2X1
inches), which is renewed from time to time. (Tin containers are not used as the
camphor must be allowed to volatilize into the open.) No more than five boxes
are placed one on top of the other. The positives and negatives are carefully
inspected at least twice a year.
Among numerous positives and negatives that I was allowed to inspect was a
picture taken in 1913. I was astonished to find both positive and negative per-
fectly satisfactory; fresh, smooth, and unshrunk, as I proved by comparison
with a piece of fairly new raw material.
As I was told, the humidity of the air is always about 70 to 80 per cent, due to
the fact that many lakes are close by. The temperature in the storehouse is said
to be about 20° to 22 °C. in summertime, and not less than 10 °C. in the winter-
time. Those in charge are convinced that the films can be kept in absolutely
proper condition for at least 30 to 40 years. At Reichsarchiv the old simple
camphor method works so well that it is followed by some of the great cities, for
instance, Bremen.
(Signed) ERICH EWARTH
The following are particular points of interest concerning the method of storing
the film:
(1) The interior of the building was made dark by enclosing the windows, as
experience had shown that light affected the condition of the film unfavorably.
(2) Shelves were built along the walls and in the middle of the room.
(3) No attempt was made to regulate the temperature, although it was
thought that an improvement would result if the temperature were maintained
constant at about 20 °C.; this has not been done because of financial considera-
tions.
530 PRESERVATION OF FILM COMMITTEE
(4) The best value of relative humidity is thought to be 60 to 70 per cent.
(5) Boxes for storage are square and all are of the same size, and may contain
up to 400 meters of film. The camphor is placed in one corner of the box and is
wrapped in paper to keep it from making contact with the films. Pure camphor is
used.
(6) No chemical action occurs between the camphor and the base or emulsion.
The camphor replaces the original content in the base.
(7) The camphor in each box is renewed twice a year.
(8) Fifty to sixty thousand meters of film are stored in this room. No special
attention is given to winding the films except to wind them more loosely than
ordinarily. The film is stored flat, not more than five boxes being placed one
above the other.
(9) All film is inspected twice a year, and if any white spots are found they
are wiped off with a cloth. This white deposit does not injure the film.
(10) Both positive and negative are handled in the same way. The method
described has been followed for fifteen years.
(11) Water in sponges has been experimented with, but with unsatisfactory
results.
REPORT OF THE MUSEUM COMMITTEE*
The work of this Committee in preserving the traditions and relics
of the motion picture has gone steadily forward during the past year.
A majority of the pioneers of the industry are represented by relics of
their endeavors in this collection, which is being brought together
under the sponsorship of the S. M. P. E.
All phases of the industry are represented, and the exhibits are so
arranged and labeled at the Los Angeles Museum that either a student
or a casual visitor will benefit from a visit to the collection.
A few of the more important accessions to the collection that have
been placed on display are the miniature sets enclosed in diorama
cases. There are two of these sets: one representing a sound stage
in operation, wherein is shown in scale all the paraphernalia necessary
for shooting a sound picture; and the other showing the technic of
shooting a glass process shot. This last-named set was arranged by
Mr. Willis O'Brien, whose most recent picture was King Kong; in it
are shown the elements necessary in creating one of the glass atmos-
phere scenes. The sound set was made by Mr. Carrol Shepphird,
who is now making a miniature of the first Edison studio. The RKO
studio has made available a collection of devices used for creating
sounds artificially. The preservation and display of these devices is a
debatable question ; but as the improvements in recording apparatus
will shortly eliminate them, it should be a good policy to preserve a
record of them even though many in the industry may feel that the
picture-going public should not be acquainted with this phase of pic-
ture making. A further record of the present has been made available
by each of the studios in the form of a collection of still photographs
showing their players in studio atmosphere. Many other items of
the present are being preserved, so that an accurate record may be
available of the trend of motion picture history. Any one having
documents or literature showing new developments should send them
to the Motion Picture Department of the Los Angeles Museum so
that these records may be made complete for future reference.
The bringing together of the relics of the past has not been over-
* Presented at the Spring, 1933, Meeting at New York, N. Y.
531
532 MUSEUM COMMITTEE [j. s. M. P. E.
looked. Mr. George E. Van Guysling, who was manager of the Bio-
graph Co. from 1904 to 1907, and an exhibitor prior to that, added to
the collection many historical relics. Included among these is a set of
catalogues of the first 3000 pictures made by Biograph, a copy of the
first Film Index, which was the first trade journal of the motion pic-
ture industry, and catalogues of companies that manufactured appa-
ratus about 1900. Mr. Van Guysling brought to light the date of the
first company to begin making pictures on the West Coast, the Bio-
graph Co., which organized a studio in Los Angeles at 2623 West Pico
St., on March 6, 1906. This date has been authenticated by various
documents. The collaboration of Mr. Van Guysling with the Com-
mittee is greatly appreciated, and his display of many relics of the
past is an interesting and valuable addition to the collection.
Another collection is the group of memoirs of the Vitagraph Co.,
made available by Mr. J. Stuart Blackton. In this accession is a
large painting of the first Vitagraph open-air studio on top of the
Morse Building on Nassau Street, in New York. This painting shows
the set, as well as the furniture, which was painted on the wall of the
adjoining building. Other items are a copy of the first magic lantern
made by Athanasius Kircher, in 1640, early Zootropes, a copy of the
first fan magazine, autographed by Edison and all the members of
the "Patents Company." Mr. Blackton also gave the museum a Bio-
graph Mutoscope with a complete motion picture of 1908, showing
pictures of the members of the Patents Company. This picture is in
the form of a series of cards mounted on a hub. The cards are ar-
ranged to be flipped in order to show motion.
Mr. H. Lyman Broening presented an Edison projector and a com-
plete set of bulletins of all Biograph pictures of 1908-09. It is in-
teresting to note that this company made over 200 pictures during
those two years, which varied from 500 to 900 feet in length. On the
bulletins are pictures of motion picture players, many of whom are
still famous, such as Mary Pickford, Mack Sennett, Florence Law-
rence, Marion Leonard, Henry B. Walthall, and others.
Mr. Walt Disney made a display illustrating the making of a car-
toon of Mickey Mouse. He also gave a set of drawings from his first
three-color pictures as used in making animated cartoons.
Mr. Walt Lantz, who had the distinction of making the first car-
toon in color, made available a copy of this cartoon, as well as ex-
amples of his work in cartoon processes in 1917. Mr. Ted Eshbaugh,
another pioneer in color cartoons, is making a display.
June, 1933] MUSEUM COMMITTEE 533
Others assisting in the formation of this exhibit are Mr. Mack
Sennett, who lent a representative group of early cameras, as well
as memoirs of the early " Keystone Cop." Mr. Paul Panzer, who was
known as the Pathe villain in the early days, has made available some
posters of the nickelodeon theater of the time when the names of
players were not publicized. Mr. Otto K. Olesen has presented a
group of various arc lights that were used universally in making
pictures prior to the advent of sound. The Bausch & Lomb Optical
Co. has assured the Committee that it will make a display of lenses
showing all types used from the earliest days of photography to the
present. The RCA Victor Co. and the Western Electric Co. have
promised displays illustrating their sound equipment. Mr. Leo G.
Young in his searches through early periodicals has uncovered many
interesting illustrations of early movie devices which he has copied for
the exhibit.
One of the highlights of the exhibit is the display of original speci-
mens of motion picture film. This collection includes samples of film
dating back to the beginning of motion pictures, when both Friese-
Greene and Edison were struggling with the idea of motion in pic-
tures. There are also samples of the first raw stock made by George
Eastman in 1889. In this collection, the majority of pioneers who
made pictures before 1900 are represented by specimens of film from
their work. A graphic history of color and motion pictures, as well as
cartooning and other processes of the industry is afforded by this col-
lection. There are examples of pictures made on paper, collodion,
and metal. The film specimens are bound between glass plates, and
are mounted in special cases having back-lighting facilities. Ac-
companying each specimen is a historical notation. All inventors
who have perfected processes are requested to send samples of their
work on film, so that a complete record of the ramifications of the
motion picture may be preserved in this manner, to the chairman of
this Committee, care of the New York office of the Society. Credit
is given the donor on the museum label.
It would be impossible to list all the contributors who have assisted
in the work of this committee ; Wallace Clendenin, Ransom Mathews,
Leo G. Young, Jackson J. Rose, Louis B. Mayer, Lee de Forest,
Douglas Fairbanks, Bill Cotterell, Lee Shippey, Jack Lewis, Mario
Larrinaga, Byron Crabbe, Silas Snyder, George Blaisdell, and Una
Theisen are only a few of those whose assistance has been gladly ren-
dered and greatly appreciated.
534 MUSEUM COMMITTEE [j. s. M. P. E.
E. THEISEN, Chairman
G. A. CHAMBERS W. V. D. KELLEY
B. W. DEPUE G. E. MATTHEWS
O. B. DEPUE T. RAMSAYE
C. L. GREGORY A. REEVES
C. F. JENKINS F. H. RICHARDSON
A. F. VICTOR
DISCUSSION
MR. K. KALLMAN: As the Society is endeavoring to establish an exhibit also
at the New York Museum of Science and Industry, it might be appropriate to
say a few brief words about the Museum and what it is doing.
The Museum is situated at 220 East 42nd Street, New York, N. Y. The
exhibits, which are strictly educational, are devoted to the major divisions of
what might be called the essentials of civilization: food, industries, shelter,
transportation, textiles, and the like. Visitors are encouraged to handle the
exhibits, and to push controlling buttons and to turn cranks. Most of the
exhibits can be operated ; in the communications section, for instance, is a model
of a dial telephone arranged to show how it operates. There is an oscillograph
arranged so that the visitor can see his voice vibrations. In transportation,
there are wind tunnels, locomotive models, etc. A large section is devoted to
electrical science, where are shown the complete development and theory of
magnetism and electricity by means of models that are for the most part opera-
tive. The average attendance at the Museum is 800 per day.
The motion picture exhibit that we are trying to develop will be housed, we
hope, in a room approximately 750 square feet in area. We should like to as-
semble an exhibit in New York primarily for two reasons. First, the motion
picture industry actually began in New York. The old Biograph Company
and some of the older companies started here. Second, we have the largest
population, and a greater proportion of the population goes to see motion pictures
in New York than any other place in the world. We feel that we want to build
up this exhibit and try to rival Mr. Theisen's exhibit out in Los Angeles.
MR. J. I. CRABTREE: The question is, how are we going to do it? It will
require a lot of money, even after we have contributed the apparatus. I do
not know whether you have seen the Will Day exhibits in the South Kensington
Museum in England. They are housed in mahogany and glass cases, and by
turning a handle on the outside of the case, the exhibits can be made to work.
MR. KALLMAN: It is quite a problem to demonstrate the exhibits and to make
them fool-proof so that they can not be broken or stolen; but that, I believe, is
the problem of the Museum staff and I think we are able to cope with the situa-
tion. A purely historical exhibit would be interesting, but it is just as important
to explain modern equipment — the theory of sound motion pictures, for example.
We have already planned to have a demonstrating model of photoelectric cells
and amplifier tubes and things of that sort. It is really our purpose to explain
the newer things, and how they are being done, to the public of New York City.
MR. CRABTREE: Is the Museum interested purely in these working models,
or in historical pieces of equipment — or both? If it is interested only in working
June, 1933] MUSEUM COMMITTEE 535
models, then it seems to me that this Museum is not the place for our equipment.
MR. KALLMAN: One of our typical exhibits is in the food section, where we
have a series of models built to scale showing the development of plows. They
are static exhibits, the first section showing a primitive man pulling a forked
stick through the ground — the early method of plowing. The next section
shows a later development, the application of the wheel; and finally, the seventh
or eighth section shows the modern steel plow drawn by horses. It would have
been too complicated to build a combined harvesting machine to scale, so at
that point of the story we insert a motion picture — 16 mm. — to complete the
story of the development of plows.
So it is our problem not only to make the exhibits operate wherever possible,
but also to present the historical background of the particular development as
well.
SOCIETY OF MOTION PICTURE
ENGINEERS
OFFICERS
1933
President
A. N. GOLDSMITH, 444 Madison Ave., New York, N. Y.
Past-President
J. I. CRABTRBE, Eastman Kodak Company, Rochester. N. Y.
Vice-Presidents
E. I. SPONABLE, Fox Film Corp., New York. N. Y.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
Secretary
J. H. KURLANDER, Westmghouse Lamp Co., Bloomfield, N. J.
Treasurer
H. T. COWLING, Rochester, N. Y.
Board of Governors
H. T. COWLING, 1430 Monroe Ave., Rochester, N. Y.
J. I. CRABTREE, Research Laboratories, Eastman Kodak Co., Rochester, N. Y.
P. H. EVANS, Warner Bros. Pictures, Inc., 1277 E. 14th St., Brooklyn. N. Y.
R. E. FARNHAM, General Electric Co., Nela Park, Cleveland, Ohio.
O. M. GLUNT, Bell Telephone Laboratories, Inc., New York, N. Y.
A. N. GOLDSMITH. 444 Madison Ave., New York, N. Y.
H. GRIFFIN, International Projector Corp., 96 Gold St., New York, N. Y.
W. C. HUBBARD, General Electric Vapor Lamp Co., Hoboken, N. J.
E. HUSE, Eastman Kodak Co., 6706 Santa Monica Ave., Hollywood, Calif.
W. C. KUNZMANN, National Carbon Co., Cleveland, Ohio.
J. H. KURLANDER, Westinghouse Lamp Co., Bloomfield, N. J.
R. F. MITCHELL, Bell & Howell Co., 1801 Larchmont Ave., Chicago, 111.
E. I. SPONABLE, Fox Film Corp.. 850 Tenth Ave., New York, N. Y.
536
SOCIETY ANNOUNCEMENTS
JOINT MEETING OF BOARD OF GOVERNORS AND CHAIRMEN OF COMMITTEES
On the morning of April 24, at the Hotel Pennsylvania, New York, N. Y.,
was held a joint meeting of members of the Board of Governors and chairmen of
committees of the Society. The purpose of the meeting was to discuss the rela-
tions between the various committees and their relation to the Society as a whole;
to determine ways and means of assuring the greatest degree of collaboration
between the committees; to define more carefully the scope of the work of each
committee so that there may be no duplication of effort; and to provide an
opportunity for each committee to learn of the methods followed by each other
committee that have proved advantageous.
Eleven committees were represented at this meeting, which proved to be very
fruitful in respect to arousing a clear understanding of the functions and relations
of the committees, and of the ways in which they might be of greatest service to
each other and to the Society. The general attitude of the industry toward sup-
plying technical information and data to the committees received special con-
sideration, particularly with reference to the curtailing of technical activities under
economic duress.
The value of this first joint meeting was so evident that it is planned to hold a
similar meeting in the future at each convention.
NEW YORK SECTION
The regular monthly meeting of the New York Section was held on May 17,
at the Electrical Institute, in the Grand Central Palace, New York, N. Y. Under
the supervision of the Projection Practice Committee, Mr. H. Rubin, Chairman,
the following papers were presented:
"The Professional Projectionist," by Dr. A. N. Goldsmith.
"Operating Disadvantages of Sound Screens," by Mr. F. H. Richardson.
"Effect of Oil on Film on the Screen Image," by Mr. G. C. Edwards.
"Factors Affecting Sound Reproduction in Theaters," by Mr. J. O. Baker.
The meeting was well attended, and considerable discussion followed the presen-
tation of the papers. Some discussion occurred also concerning a proposed
change of the form of the travel-ghost target included in the test reel presented to
the Society with the report of the Projection Practice Committee at the New
York Convention, on April 26. The new form of the target, as presented by
Chairman Rubin, was approved by the meeting, and will be described in the
report of the Committee when published in the JOURNAL.
537
538 SOCIETY ANNOUNCEMENTS
CHICAGO SECTION
The monthly meeting of the Chicago Section was held on May 11, at the Elec-
tric Association, in the Civic Opera Building, Chicago, 111., preceded by an informal
dinner. A report on the various features of the New York Convention was
presented to the Section by Mr. R. F. Mitchell, Chairman, for the benefit of those
who could not attend the Convention. Mr. Mitchell presented also summaries
of the various technical papers, and described the general condition of the motion
picture industry as reflected by the activities of the New York Convention.
The meeting was well attended; and, as it was the last meeting of the current
season, plans were laid for the Fall activities of the Section, with the view of
making that season even more successful than the past one.
SUSTAINING MEMBERS
Bausch & Lomb Optical Co.
Bell Telephone Laboratories
Burnett-Timken Laboratories
Eastman Kodak Co.
Electrical Research Products, Inc.
National Carbon Co.
RCA Victor Co., Inc.
HONOR ROLL
OF THE
SOCIETY OF MOTION PICTURE ENGINEERS
By action of the Board of Governors, October 4, 1931, this Honor Roll was estab-
lished for the purpose of perpetuating the names of distinguished pioneers who are
now deceased;
Louis AIME AUGUSTIN LE PRINCE
WILLIAM FRIESE-GREENE
THOMAS ALVA EDISON
GEORGE EASTMAN
JEAN ACME LE ROY
AUTHOR INDEX, VOLUME XX
JANUARY TO JUNE, 1933
BOTHAMLEY, C. H.
CAPORALE, P.
CRABTREE, J. I.
(and IVES, C. E.,
arid MUEHLER, L. E.)
DAILY, C. R.
FETTER, C. H.
GARITY, W.
GOODWIN, W. N., JR.
GUNDELFINGER, A. M.
HERRIOTT, W.
HICKMAN, K.
(and HYNDMAN, D. E.)
HINELINE, H. D.
HYNDMAN, D. E.
Cand HICKMAN, K.)
IVES, C. E.
(and MUEHLER, L. E.,
and CRABTREE, J. I.)
MENDOZA, D.
MUEHLER, L. E.
(and CRABTREE, J. I.,
and IVES, C. E.)
NEWCOMER, H. S.
READ, S., JR.
Issue Page
Early Stages of Kinematography March 263
Musical Acoustics of Auditoriums Feb. 119
Making a Fade-Out by After Treat-
ment Jan. 65
A New Western Electric Double Film
Portable Sound Recording System Feb. 128
A New Way of Splitting Seconds April 332
The Production of Animated Cartoons April 309
The Photronic Photographic Exposure
Meter Feb. 95
A Method for the Calculation of the
Correct and Most Economical Con-
centrations of Elon and Hydroqui-
none in a Borax Developer for Motion
Picture Film April 343
A Method of Measuring Axial Chro-
matic Aberration in an Objective
Lens April 323
Model Making with Sheet Film Base March 236
Composite Photographic Processes April 283
Model Making with Sheet Film Base March 236
Making a Fade-Out by After Treat-
ment Jan.
Practical Problems in the Recording
and Reproduction of Music for Mo-
tion Pictures
Jan.
Making a Fade-Out by After Treat-
ment Jan.
Wide Screen Photography with Cylin-
drical Anamorphosing Systems and
Characteristics of Motion Picture
Lenses and Images Jan.
RCA Victor High Fidelity Film Re-
cording Equipment May
65
79
65
31
396
539
540
INDEX
REID, C. D.
(and TUTTLE, F.)
RICHARD, A. P.
RICHARDSON, F. H.
SNELL, P. A.
STOYANOWSKY, A. T.
THEISEN, E.
THEISEN, E.
TUTTLE, C.
TUTTLE, F.
(and REID, C. D.)
WEIL, F.
WHITE, D. R.
ZIMMERMAN, A. G.
Issue Page
The Problem of Motion Picture Pro-
jection from Continuously Moving
Film Jan. 3
Remarks on the Making of Sound
Records on Lenticular Color Films Jan. 60
Avoidance of Eye Fatigue May 391
An Introduction to the Experimental
Study of Visual Fatigue May 367
A New Process of Television Out of
Doors May 437
The Depicting of Motion Prior to the
Advent of the Screen March 249
The History of Nitrocellulose as a Film
Base March 259
The Relation between Diffuse and
Specular Density March 228
The Problem of Motion Picture Pro-
jection from Continuously Moving
Film Jan. 3
The Optical-Photographic Principles of
the Agfacolor Process April 301
Photographic Effects Obtained with
Infra D Negative Jan. 54
Film Recorders March 211
CLASSIFIED INDEX, VOLUME XX
JANUARY TO JUNE, 1933
Aberration.
A Method of Measuring Axial Chromatic Aberration in an Objective Lens,
W. HERRIOTT, No. 4 (April), p. 323.
Acoustics.
Musical Acoustics of Auditoriums, P. CAPORALE, No. 2 (February), p. 119.
Report of the Sound Committee, No. 6 (June), p. 500.
Aerial Photography.
Photographic Effects Obtained with Infra D Negative, D. R. WHITE, No. 1
(January), p. 54.
Animation.
The Production of Animated Cartoons, W. GARITY, No. 4 (April), p. 309.
Applied Motion Pictures.
A New Way of Splitting Seconds, C. H. FETTER, No. 4 (April), p. 332.
Apparatus, General.
New Apparatus, No. 1 (January), p. 84.
Camera Accessories.
New Apparatus, No. 1 (January), p. 84.
The Photronic Photographic Exposure Meter, W. N. GOODWIN, JR., No. 2
(February), p. 95.
Cartoons.
The Production of Animated Cartoons, W. GARITY, No. 4 (April), p. 309.
Cinematography, History of.
The Depicting of Motion Prior to the Advent of the Screen, E. THEISEN, No. 3
(March), p. 249.
Early Stages of Kinematography, C. H. BOTHAMLEY, No. 3 (March), p. 263.
Color Photography.
Remarks on the Making of Sound Records on Lenticular Color Films, A. P.
RICHARD, No. 1 (January), p. 60.
The Optical- Photographic Principles of the Agfacolor Process, F. WEIL, No. 4
(April), p. 301.
Committees.
Care and Development of Film, No. 1 (January), p. 90.
Care and Development of Film, No. 3 (March), pp. 183 and 199.
Museum, No. 3 (March), p. 276.
541
542 INDEX [j. s. M. P. E.
Museum, No. 6 (June), p. 531.
Papers, No. 3 (March), p. 275.
Preservation of Film, No. 6 (June), p. 523.
Progress, No. 6 (June), p. 459.
Projection Practice, No. 2 (February), p. 178.
Projection Practice, No. 4 (April), p. 362.
Projection Screens, No. 3 (March), p. 277.
Projection Screens, No. 6 (June), p. 510.
Projection Theory, No. 6 (June), p. 521.
Sound, No. 3 (March), p. 276.
Sound, No. 6 (June), p. 500.
Screen Brightness, No. 3 (March), p. 277.
Screen Brightness, No. 4 (April), p. 362.
Standards and Nomenclature, No. 1 (January), p. 91.
Standards and Nomenclature, No. 2 (February), p. 178.
Standards and Nomenclature, No. 3 (March), p. 276.
Standards and Nomenclature, No. 6 (June), p. 517.
Studio Lighting, No. 6 (June), p. 517.
Sub-Committee on Exchange Practice, No. 3 (March), pp. 199 and 277.
Sub-Committee on Laboratory Practice, No. 3 (March), p. 183.
Composite Photography.
Composite Photographic Processes, H. D. HINELINE, No. 4 (April), p. 283.
Constitution and By-Laws.
Addition to By-Law VII, No. 5 (May), p. 454.
Continuous Projectors.
The Problem of Motion Picture Projection from Continuously Moving Film,
F. TUTTLE and C. D. REID, No. 1 (January), p. 3.
Densitometry.
The Relation between Diffuse and Specular Density, C. TUTTLE, No. 3 (March)
p. 228.
Developers for Motion Picture Film.
A Method for the Calculation of the Correct and Most Economical Concentra-
tions of Elon and Hydroquinone in a Borax Developer for Motion Picture
Film, A. M. GUNDELFINGER, No. 4 (April), p. 343.
Equipment Portable.
A New Western Electric Double Film Portable Sound Recording System, C. R.
DAILY, No. 2 (February), p. 128.
Exchange Practice.
Committee on the Care and Development of Film, No. 1 (January), p. 90.
Sub-Committee on Exchange Practice, No. 3 (March), pp. 199 and 277.
Exposure.
The Photronic Photographic Exposure Meter, W. N. GOODWIN, JR., No. 2
(February), p. 95.
June, 1933] INDEX 543
Eye-Strain.
An Introduction to the Experimental Study of Visual Fatigue, P. A. SNELL,
No. 5 (May), p. 367.
Avoidance of Eye Fatigue, F. H. RICHARDSON, No. 5 (May), p. 391.
Fades.
Making a Fade-Out by After Treatment, C. E. IVES, L. E. MUEHLER, and J. I.
CRABTREE, No. 1 (January), p. 65.
Film, Development of.
Report of the Committee on the Care and Development of Film, No. 3
(March), pp. 183 and 199.
A Method for the Calculation of the Correct and Most Economical Concen-
trations of Elon and Hydroquinone in a Borax Developer for Motion Picture
Film, A. M. GUNDELFINGER, No. 4 (April), p. 343.
Film, History of.
The History of Nitrocellulose as a Film Base, E. THEISEN, No. 3 (March),
p. 259.
Film Phonograph.
Film Recorders, A. G. ZIMMERMAN, No. 3 (March), p. 211.
Film, Photographic Characteristics.
Photographic Effects Obtained with Infra D Negative, D. R. WHITE, No. 1
(January), p. 54.
Historical.
The Depicting of Motion Prior to the Advent of the Screen, E. THEISEN, No.
3 (March), p. 249.
The History of Nitrocellulose as a Film Base, E. THEISEN, No. 3 (March),
p. 259.
Early Stages of Kinematography, C. H. BOTHAMLEY, No. 3 (March), p. 263.
Composite Photographic Processes, H. D. HINELINE, No. 4 (April), p. 283.
(See also "Museum.")
Infra-Red Photography.
Photographic Effects Obtained with Infra D Negative, D. R. WHITE, No. 1
(January), p. 54.
Laboratory Apparatus.
Film Recorders, A. G. ZIMMERMAN, No. 3 (March), p. 211.
Model Making with Sheet Film Base, K. HICKMAN and D. E. HYNDMAN,
No. 3 (March), p. 236.
RCA Victor High Fidelity Film Recording Equipment, S. READ, JR., No. 5
(May), p. 396.
Laboratory Practice.
Committee on the Care and Development of Film, No. 1 (January), p. 90.
Sub-Committee on Laboratory Practice, No. 3 (March), p. 183.
544 INDEX [j. s. M. P. E.
Lantern Slides.
Engineering and Scientific Charts for Lantern Slides, No. 2 (February), p. 142.
Lenses.
A Method of Measuring Axial Chromatic Aberration in an Objective Lens,
W. HERRIOTT, No. 4 (April), p. 323.
Wide Screen Photography with Cylindrical Anamorphosing Systems and
Characteristics of Motion Picture Lenses and Images, H. S. NEWCOMER,
No. 1 (January), p. 31.
Lenticular Color Films.
Remarks on the Making of Sound Records on Lenticular Color Films, A. P.
RICHARD, No. 1 (January), p. 60.
The Optical- Photographic Principles of the Agfacolor Process, F. WEIL, No. 3
(April), p. 301.
Lighting.
Report of the Studio Lighting Committee, No. 6 (June), p. 517.
Measurements, Optical.
A Method of Measuring Axial Chromatic Aberration in an Objective Lens,
W. HERRIOTT, No. 4 (April), p. 323.
Membership.
List of Members, No. 2 (February), p. 151.
Meters.
The Photronic Photographic Exposure Meter, W. N. GOODWIN, JR., No. 2
(February), p. 95.
Miscellaneous.
Engineering and Scientific Charts for Lantern Slides, No. 2 (February), p. 142.
A New Way of Splitting Seconds, C. H. FETTER, No. 4 (April), p. 332.
Model Making.
Model Making with Sheet Film Base, K. HICKMAN and D. E. HYNDMAN,
No. 3 (March), p. 236.
Museum.
Museum Committee, No. 3 (March), p. 276.
• Report of the Museum Committee, No. 6 (June), p. 531.
Music.
Practical Problems in the Recording and Reproduction of Music for Motion
Pictures, D. MENDOZA, No. 1 (January), p. 79.
Musical Acoustics of Auditoriums, P. CAPORALE, No. 2 (February), p. 119.
Non-Intermittent Projection.
The Problem of Motion Picture Projection from Continuously Moving Film,
F. TUTTLE and C. D. REID, No. 1 (January), p. 3.
June, 1933] INDEX 545
Objectives.
A Method of Measuring Axial Chromatic Aberration in an Objective Lens,
W. HERRIOTT, No 4 (April), p. 323.
Ocular Fatigue.
An Introduction to the Experimental Study of Visual Fatigue, P. A. SHELL,
No. 5 (May), p. 367.
Avoidance of Eye Fatigue, F. H. RICHARDSON, No. 5 (May), p. 391.
Optics.
Wide Screen Photography with Cylindrical Anamorphosing Systems and
Characteristics of Motion Picture Lenses and Images, H. S. NEWCOMER,
No. 1 (January), p. 31.
A Method of Measuring Axial Chromatic Aberration in an Objective Lens,
W. HERRIOTT, No. 4 (April), p. 323.
Papers.
Papers Committee, No. 3 (March), p. 275.
Photography.
The Photronic Photographic Exposure Meter, W. N. GOODWIN, JR., No. 2
(February), p. 95.
Photography, Wide Screen.
Wide Screen Photography with Cylindrical Anamorphosing Systems and
Characteristics of Motion Picture Lenses and Images, H. S. NEWCOMER,
No. 1 (January), p. 31.
Preservation of Film.
Report of the Committee on the Preservation of Film, No. 6 (June), p. 523.
Processing.
A Method for the Calculation of the Correct and Most Economical Concentra-
tions of Elon and Hydroquinone in a Borax Developer for Motion Picture
Film, A. M. GUNDELFINGER, No. 4 (April), p. 343.
Process Photography.
Composite Photographic Processes, H. D. HINELINE, No. 4 (April), p. 283.
Progress.
Progress in the Motion Picture Industry, No. 6 (June), p. 459.
Projection, General Information.
Avoidance of Eye Fatigue, F. H. RICHARDSON, No. 5 (May), p. 391.
Projection Practice.
Projection Practice Committee, No. 2 (February), p. 178.
. Projection Practice Committee, No. 4 (April), p. 362.
Projection Screens.
Committee on Screen Brightness, No. 3 (March), p. 277.
Projection Screens Committee, No. 3 (March), p. 277.
546 INDEX [j. s. M. P. E.
Sub- Committee on Screen Brightness and Theater Illumination, No. 4 (April),
p. 362.
Report of the Projection Screens Committee, No. 6 (June), p. 510.
Projection Theory.
Report of the Projection Theory Committee, No. 6 (June), p. 521.
Projectors, Continuous.
The Problem of Motion Picture Projection from Continuously Moving Film,
F. TUTTLE and C. D. REID, No. 1 (January), p. 3.
Recorders.
A New Western Electric Double Film Portable Sound Recording System,
C. R. DAILY, No. 2 (February), p. 128.
Film Recorders, A. G. ZIMMERMAN, No. 3 (March), p. 211.
RCA Victor High Fidelity Film Recording Equipment, S. READ, JR., No. 5
(May), p. 396.
Re-recording.
Film Recorders, A. G. ZIMMERMAN, No. 3 (March), p. 211.
Screens.
Committee on Screen Brightness, No. 3 (March), p. 277.
Projection Screens Committee, No. 3 (March), p. 277.
Sub-Committee on Screen Brightness and Theater Illumination, No. 4 (April),
p. 362.
Report of the Projection Screens Committee, No. 6 (June), p. 510.
Sensitometry.
The Relation between Diffuse and Specular Density, C. TUTTLE, No. 3 (March),
p. 228.
Sound Committee.
Sound Committee, No. 3 (March), p. 276.
Report of the Sound Committee, No. 6 (June), p. 500.
Sound Recording, with Color.
Remarks on the Making of Sound Records on Lenticular Color Films, A. P.
RICHARD, No. 1 (January), p. 60.
Sound Recording, Variable Density Method.
A New Western Electric Double Film Portable Sound Recording System, C. R.
DAILY, No. 2 (February), p. 128.
Sound Recording, Variable Width Method.
Film Recorders, A. G. ZIMMERMAN, No. 3 (March), p. 211.
RCA Victor High Fidelity Film Recording Equipment, S. READ, JR., No. 5
(May), p. 396.
June, 1933] INDEX 547
Sound Reproduction, General Information.
Practical Problems in the Recording and Reproduction of Music for Motion
Pictures, D. MENDOZA, No. 1 (January), p. 79.
Standards and Nomenclature.
Committee on Standards and Nomenclature, No. 1 (January), p. 91.
Standards, No. 2 (February), p. 178.
Standards Committee, No. 3 (March), p. 276.
Report of the Standards and Nomenclature Committee, No. 6 (June), p. 505.
Studio Lighting.
Report of the Studio Lighting Committee, No. 6 (June), p. 517.
Television.
A New Process of Television Out of Doors, A. T. STOYANOWSKY, No. 5 (May),
p. 437.
Technical Motion Picture Photography.
A New Way of Splitting Seconds, C. H. FETTER, No. 4 (April), p. 332.
Trick Photography.
Composite Photographic Processes, H. D. HINELINE, No. 4 (April), p. 283.
The Production of Animated Cartoons, W. GARITY, No. 4 (April), p. 309.
Visual Fatigue.
An Introduction to the Experimental Study of Visual Fatigue, P. A. SNELL,
No. 5 (May), p. 367.
Avoidance of Eye Fatigue, F. H. RICHARDSON, No. 5 (May), p. 391.
Wide Pictures.
Wide Screen Photography with Cylindrical Anamorphosing Systems and
Characteristics of Motion Picture Lenses and Images, H. S. NEWCOMER,
No. 1 (January), p. 31.
WHAT
1933 DEMANDS
» » » I NOT simply quality, but FIRST
quality, is the watchword today.
The pictures that "go over big"
are being made under conditions
and with materials that promise
nothing but outstanding excel-
lence .... So look to your film!
Use Eastman Sound Recording
Film, and you can be sure that
the sound you work so hard to
perfect will come out unimpaired
through the silvered screens of a
critical movie world. This film
gives what 1933 demands! Eastman
Kodak Company, Rochester, New
York. (J. E. Brulatour, Inc., Dis-
tributors, New York, Chicago,
Hollywood.)
EASTMAN
SOUND RECORDING FILM
Live Music
Archive
Librivox
Free Audio
Metropolitan Museum
Cleveland
Museum of Art
Internet
Arcade
Console Living Room
Open Library
American
Libraries
TV News
Understanding
9/11